In Circuit Transistor Checker

This simple circuit has helped me out on many occasions. It is able to check transistors, in the circuit, down to 40 ohms across the collector-base or base-emitter junctions. It can also check the output power transistors on amplifier circuits. Circuit operation is as follows. The 555 timer ( IC1 ) is set up as a 12hz multi vibrator. The output on pin 3 drives the 4027 flip-flop ( IC2). This flip-flop divides the input frequency by two and delivers complementary voltage outputs to pin 15 and 14. The outputs are connected to LED1 and LED2 through the current limiting resistor R3.

Circuit Diagram

The LEDs are arranged so that when the polarity across the circuit is one way only one LED will light and when the polarity reverses the other LED will light, therefore when no transistor is connected to the tester the LEDs will alternately flash. The IC2 outputs are also connected to resistors R4 and R5 with the junction of these two resistors connected to the base of the transistor being tested. With a good transistor connected to the tester, the transistor will turn on and produce a short across the LED pair. If a good NPN transistor is connected then LED1 will flash by itself and if a good PNP transistor is connected then LED2 will flash by itself. If the transistor is open both LEDs will flash and if the transistor is shorted then neither LED will flash.

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Simple Low Drop 5V Regulator

A 4-cell pack is a convenient, popular battery size. Alkaline manganese batteries are sold in retail stores in packs of four, which usually provide sufficient energy to keep battery replacement frequency at a reasonable level. Generating 5 V from four batteries is, however, a bit tricky. A fresh set of four batteries has a terminal voltage of 6.4 V, but at the end of their life, this voltage is down to 3.2 V. Therefore, the voltage needs to be stepped up or down, depending on the state of the batteries. A flyback topology with a costly, custom designed transformer could be used, but the circuit in the diagram gets around the problem by using a flying capacitor together with a second inductor.

Circuit diagram:

The circuit also isolates the input from the output, allowing the output to go to 0 V during shutdown. The circuit can be divided conceptually into boost and buck sections. Inductor L1 and switch IC1 comprise the boost or step-up section, and inductor L2, diode D1 and capacitor C3 form the buck or step-down section. Capacitor C2 is charged to the input voltage, Vin, and acts as a level shift between the two sections. The switch toggles between ground and Vin+Vout , while the junction of L2, C2 and D1 toggles between –Vin and Vout +Vd1. Efficiency is directly related to the quality of the capacitors and inductors used.

Better quality capacitors are more expensive. Better quality inductors need not cost more, but normally take up more space. The Sanyo capacitors used in the prototype (C1–C3) specify a maximum ESR (effective series resistance) of 0.045 ½ and a maximum ripple current rating of 2.1 A. The inductors used specify a maximum DCR (direct current resistance) of 0.058 ½. Worst-case r.m.s. current through capacitor C2 occurs at minimum input voltage, that is, 400 mA at full load with an input voltage of 3 V. 

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Digital Bike Tachometer SP

This digital SP tachometer for bikes uses 2 reed switches to urge the speed data of the bicycle. The reed switches are put in close to the rim of the wheel where permanent magnets pass by. The permanent magnets are connected to the wheelspokes and activate the reed switches everytime they pass by it. The speed is digitally displayed.

The tachometer circuit works in step with this principle; the pulses created by the reed contacts are counted inside an explicit time interval. The ensuing count is then displayed and represents the speed of the bike. 2 4026 ICs are used to count the pulses, decode the counter and management 2 7-segment LED show. RS flip-flops U3 and U4 perform as anti-bounce.

Electronic bicycle SP tachometer circuit diagram

The pulses arrive at the counter’s input through gate U7. The measuring amount is set by monostable multivibrator U5/U6 and might be adjusted through potentiometer P1 so the tacho are often calibrated. The circuit U1/U2 resets the counters.

Since batteries are used to power the circuit, its not sensible to support the continual show of speed data. This circuit isnt continuously active. The circuit is activated solely once a button is pressed. a minimum of 3 permanent magnets should be put in on the wheel. The circuit are often calibrated with the assistance of another pre-calibrated tachometer.

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Step Up Converter For 20 LEDs

The circuit described here is a step-up converter to drive 20 LEDs, designed to be used as a home-made ceiling night light for a child’s bedroom. This kind of night light generally consists of a chain of Christmas tree lights with 20 bulbs each consuming 1 W, for a total power of 20 W. Here, in the interests of saving power and extending operating life, we update the idea with this simple circuit using LEDs. 

Power can be obtained from an unregulated 12 V mains adaptor, as long as it can deliver at least about 330 mA.  The circuit uses a low-cost current-mode controller type UCC3800N, reconfigured into voltage mode to create a step-up converter with simple compensation. By changing the external components the circuit can easily be modified for other applications. To use a current-mode controller as a voltage-mode controller it is necessary to couple a sawtooth ramp (rising from 0 V to 0.9 V) to the CS (current sense) pin, since this pin is also an input to the internal PWM comparator.

Circuit diagram :

Step-up Converter For 20 LEDs Circuit Diagram

The required ramp is present on the RC pin of the IC and is reduced to the correct voltage range by the voltage divider formed by R3 and R2. The RC network formed by R4 and C6 is dimensioned to set the switching frequency at approximately 525 kHz. The comparator compares the ramp with the divided-down version of the output voltage produced by the potential divider formed by R6 and R7. Trimmer P1 allows the output voltage to be adjusted. This enables the current through the LEDs to be set to a suitable value for the devices used. The UCC3800N starts up with an input voltage of 7.2 V and switches off again if the input voltage falls below 6.9 V. The circuit is designed so that output voltages of between 20 V and 60 V can be set using P1.

This should be adequate for most cases, since the minimum and maximum specified forward voltages for white LEDs are generally between 3 V and 4.5 V. For the two parallel chains of ten LEDs in series shown here a voltage of between 30 V and 45 V will be required. The power components D1, T1 and L1 are considerably over specified here, since the circuit was originally designed for a different application that required higher power. To adjust the circuit, the potentiometer should first be set to maximum resistance and a multimeter set to a 200 mA DC current range should be inserted in series with the output to the LEDs. Power can now be applied and P1 gradually turned until a constant current of 40mA flows. The step-up converter is now adjusted correctly and ready for use.

www.ecircuitslab.com

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Flashing LED Battery status Indicator

Signals when an on-circuit battery is exhausted 5V to 12V working voltage

A Battery-status Indicator circuit will also be useful, mainly to observe portable Test-gear units and equivalent devices. LED D1 flashes to apparel the customers attention, signaling that the circuit is operating, so it's going to no longer be left on by using mistake. The circuit generates about two LED flashes per second, however the mean present drawing might be about 200µA. Transistors Q1 and Q2 are wired as an unusual complementary astable multivibrator: each are off 99% of the time, saturating best when the LED illuminates, in this case contributing to keep very low current consumption. 

Circuit diagram :

Flashing-LED Battery-status Indicator Circuit Diagram

The circuit will work with battery supply voltages within the 5 - 12V vary and the LED flashing will additionally be stopped at the desired battery voltage (comprised within the four.8 - 9V worth) by way of adjusting Trimmer R4. This vary can also be modified via altering R3 and/or R4 worth relatively.

When the battery voltage methods the onerous price, the LED flashing frequency will fall suddenly to alert the consumer. Obviously, when the battery voltage has fallen under this price, the LED will stay completely off. To maintain steady the exhausting voltage price, diode D1 was once brought to compensate Q1 Base-Emitter junction changes in temperature. The use of a Schottky-barrier device (e.g. BAT46, 1N5819 and the like) for D1 is mandatory: the circuit is no longer going to work if a common silicon diode just like the 1N4148 is used as an alternative.

Parts :

R1,R7__________220R  1/4W Resistors
R2_____________120K  1/4W Resistor
R3_______________5K6 1/4W Resistor
R4_______________5K  1/2W Trimmer Cermet or Carbon
R5______________33K  1/4W Resistor
R6_____________680K  1/4W Resistor
R8_____________100K  1/4W Resistor
R9_____________180R  1/4W Resistor
C1,C2____________4µ7  25V Electrolytic Capacitors
D1____________BAT46  100V 150mA Schottky-barrier Diode
D2______________LED  Red 5mm.
Q1____________BC547   four5V 100mA NPN Transistor
Q2____________BC557   45V 100mA PNP Transistor
B1_______________5V to 12V Battery provide
Notes :

• Mean current drawing of the circuit can be lowered further on by using elevating R1, R7 and R9 prices.

Source : Red Circuits

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LED DETECTS lightweight

All LEDs offer off lightweight of a specific color however some LEDs also are able to detect lightweight. clearly theyre not nearly as good as a tool that has been specially created to detect light; like solar cell, photocell, photo resistor, lightweight dependent resistor, photo transistor, photo diode and different photo sensitive devices.

A inexperienced LED can detect lightweight and a high-bright red LED can respond about a hundred times higher than a inexperienced LED, however the LED during this position in the circuit is classed as terribly high impedance and it needs a considerable quantity of amplification to show the detection into a worthwhile current-source. All different LEDs respond terribly poorly and arent price making an attempt. The accompanying circuit amplifies the output of the LED and permits it to be used for variety of applications.
The LED solely responds when the sunshine enters the tip of the LED and this makes it ideal for solar rackers and any time theres an outsized difference between the dark and light-weight conditions. itll not detect the
light in a very area unless the lamp is incredibly shut.

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The Gentle Touch Circuit Diagram

Consumer home equipment in this day and age hardly have a proper mains switch. Instead, appliances are fliped on and off on the contact of a button on the faraway control, similar to any other perform. This circuit displays how a tool (as lengthy because it does not draw too excessive a present) can be swaped on and off the utilization of a pushbutton. The means requires that a microcontroller is already available within the circuit, and a spare input port pin and a spare output port pin are required, along with just a little software program. When power is applied T1 initially is nonetheless fliped off. When the button is pressed the gate of T1 is taken to floor and the p-channel energy MOSFET conducts. The microcontroller circuit is now equipped with energy. Within a short duration the microcontroller must take output PB1 excessive. This activates n-channel MOSFET T1 which in flip preserves T1 turned on after the push-button is launched.

Now the microcontroller must poll the state of the push-button on its enter port (PB0) at regular intervals. Immediately after change-on it will observe that the button is pressed (a low degree on the input port pin), and it must look ahead to the button to be launched. When the button is next pressed the software should swap itself of f: to are attempting this the firmware running in the microcontroller must set the output port pin to a low stage. When the button is subsequently launched T1 will now flip off and the availability voltage will be removed from the circuit.

The circuit itself draws no present within the off state, and for (rechargeable) battery-powered appliances it is therefore absolute best to position the switch ahead of the voltage regulator. For primarys-powered instruments the change can be geared up ahead of the voltage regulator (after the rectifier and smoothing capacitor). Since there's no majors switch there will nonetheless be a small standby current draw on this case because of the transformer. Be careful not to exceed the maximum gate-source voltage specification for T1: the IRFD9024 software prompt can face up to up to 20 V. At decrease voltages R2 could be changed by way of a wire link; otherwise appropriate values for the voltage divider formed by using R1 and R2 must be chosen.

Circuit diagram:

 The Gentle Touch Circuit Diagram

The writer has arrange a small website for this challenge at http://reweb.fh-weingarten.de/elektor, which gives source code examples (which embody dealing with pushbutton contact bounce) for AVR microcontrollers suitable for use with AVR Studio and GNU C. Downloads are additionally on hand at http://www.elektor.com.

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Power Supply for Power Amplifier 200Watt By STK4050

Amplifier circuit with IC STK is tough and good quality. In this article an amplifier circuit with IC STK another base. Power "Amplifier 200Watt By STK4050" is an audio amplifier of the STK family with 200Watt power.Power Amplifier With this STK4050 can reproduce the power 200 Watts at 8 Ohm load spaker. In making Power Amplifier 200Watt With this STK4050 do not forget to provide adequate heat sink for the IC STK 4050 in order to avoid overheating.

Schematics Amplifier STK4050-STK4046

PCB Layout Amplifier

Series Power Supply for Power Amplifier 200Watt By STK4050 been displayed in one image with a series of "Power Amplifier" 200Watt With STK4050 above. IC STK 4050 in this series there are several types on the market including STK4050II, STK4050V and STK4050.

And below is a list of STK ICs are used for a good quality amplifier.

Datasheet STK IC Amplifier

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Plug Socket Wiring Detailst568astandard

Plug And Socket Wiring Details T568astandard.



Wiring Diagram For Rj 45 Cat5e Cable I T On The Go Inc Computer.



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Preamplifier for RF Sweep Generator

The RF sweep frequency generator (‘wobbu-lator’) published in the October 2008 difficulty of Elektor has a receiver option that enables the instrument for use as an instantaneous conversion receiver. This receiver does alternatively have a noise floor of best –80 dBm, which in reality will need to have been –-107 dBm to obtain a sensitivity of 1 µV. So, for a just proper receiver sommore acquire is required. A wideband amplifie however, generates a number of additional noisas well and as a consequence is not going to resuin a lot of an growth.  As an test, the author developed a make a selectionive receiver with a bandwidth of about four MHz. Because a achieve of as a minimum 35 dB is required, the preamplifier consists of two amplifying elements. 

The enter amplifier is designed round a dual gate MOSFET, sort BF982. This element produces moderately little noise but pro-vides various achieve. The output stage makes use of a BFR91A for some further achieve. Preamplifiers where both the gate and the drain are tuned steadily fight with comments by means of their  inside capacitance. Here, the drain circuit has a rather low impedance, which prevents this from taking place. In the prototype that used to be tested, the input and output are located at proper perspectives with appreciate to one another to stop inductive coupling (see photo). Despite the high achieve, the amplifier used to be completely steady even with none defensive.  The two air-cored coils in the circuit each encompass four flips and have an interior  diameter  of  6 mm,  constructed from 1-mm diameter silvered copper wire and with a tap after 1 flip.

Circuit diagram :

Preamplifier for RF Sweep Generator Circuit Diagram

 

The amplifier is principally intended for the one hundred forty four MHz beginner band, however with different coils can also be used for the FM broadcast band, as an instance. FM detection is finished via tuning near the brink of the IF filter. At an offset of 15 kHz this is only a few dB lower than on the centre of the pass-band, so that damping just isn't no longericeable. The measured sensitivity within the 2 m band used to be about 1 µV (6 dB).A good antenna always make a contributions to the reception, after all. A wideband (scanner) outside antenna will provide excellent end results. Adding this wobbulator/receiver possibility ends up in a nice reveal receiver. By environment the scan frequencies of the spectrum analyser to a hundred and forty four and 146 MHz (or 148 MHz the place applicable), any signal within this vary is in an instant visible. When a signal is detected it's basically a case of clicking the scan stop button and then clicking on the sign within the display window the usage of the right mouse howeverton. 

After this, the receiver switches instantly to this frequency and that you presumably can be ready to take heed to the signal. You can due to this fact resume the scanning so that that you could be ready to proceed to look for different alerts. For narrowband FM detection you want to make a choice the FMN howeverton in the window for the receiver and this then gives the required offset for the threshold detection at 25 kHz bandwidth. This value is adjustable by the use of the ‘setting’ menu (default is 12,500 Hz) and might be modified experimentally for best possible end results. To energy the circuit you will must use a 9-V battery. It can additionally be possible to power the amplifier immediately from the RF sweep generator, if output capacitor C6 is changed with a link; in the ‘options’ menu you're going to then must make a choice the choice ‘use probe’.

 http://www.ecircuitslab.com/2011/12/preamplifier-for-rf-sweep-generator.html

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Low Cost Universal Battery Charger Schematic

Low cost solution for charging of each NiCd and NiMh batteries

Here is the circuit diagram of a low price universal costr for NiCD - NiMH batteries. This circuit is Ideal for automobile use. It has capability to transform a primes adapter in to a costr . This one can be used to cost mobile phone, toys, moveables, video batteries, MP3 gamers, ... and has selectable cost present. An LED is situated in circuit to indicate charging. Can be built on a basic purpose PCB or a veroboard. I hope you in point of fact love it.

Picture of the circuit: 

 A Low Cost Universal Charger Circuit Schematic

Circuit diagram:

A Low Cost Universal Charger Circuit Diagram

Parts:

R1 = 120R-0...5W
R2 = See Diagram
C1 = 220uF-35V
D1 = 1N4007
D2 = 3mm. LED
Q1 = BD135
J1 = DC Input Socket

Specifications:

• Ideal for in car use.
• LED charge indication.
• Selectable cost current.
• Charges Ni Cd or NiMH batteries.
• Transforms a primarys adapter into a costr.
• Charge cellular phone, toys, transportables, video batteries …

Features:

• LED perform indication.
• Power provide polarity protected.
• Supply current: similar as cost current.
• Supply voltage: from 6.5VDC to 21VDC (depending on used battery)
• Charge present (±20%): 50mA, 100mA, 200mA, 300mA, 400mA. (selectable)

Determining the availability voltage:

This desk indicates the minimum and most voltages to supply the charger. See provide voltage choice chart under.

Example:

To cost a 6V battery a minimum supply voltage of 12V is needed, the utmost voltage is then 15V.

Voltage choice:

Voltage Selection Chart For Low Cost Universal Battery Charger

Determining the cost current:

Before constructing the circuit, you have to determinate how a lot present will probably be used to charge the battery or battery pack. It is a good suggestion to cost the battery with a present that is 10 occasions smaller then the battery capability, and to charge it for about 15 hours. If you double the charge current , then that you may charge the battery in half of the time. Charge present selection chart is positioned in diagram.

Example:

A battery pack of 6V / 1000mAh will additionally be charged with 100mA during 15 hours. If you need to charge quicker, then a cost present of 200mA can be utilized for approximately 7 hours.

Caution:

The larger cost present, the extra essential the cost time need to be checked. When faster charging is used, you should discharge the battery totally sooner than charging. Using a cost present of 1/10 of the capacity will increase the lifetime of the battery. The cost time can easily be doubled with out damaging the battery.

Note:

• Mount the transistor in conjunction with the heatsink on the PCB, bend the leads as important. Take care that the metal again of the transistor touches the heatsink. Check that the leads of the transistor don't touch the heatsink.

Source : http://www.ecircuitslab.com

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Simple Light Sensor Alarm circuit with NE555

Occurring this circuit despatched out an alarm when its LDR sensor is exposed to gentle by way of solar or lamp. A 555 steady multivariate used to be used here which sent sign a tone of about 1kHz upon detecting mild.The sensor when uncovered by mild fulls the circuit and makes the 555 oscillate at about 1kHz with transistor to pressure current.

The sensor can be shown within the circuit diagram. It has to placed making an angle of about 30 – forty five degrees to the bottom.

 Sensitivity will additionally be regulate with P1.
 This makes the solar gentle to drift via it to the bottom and stops the alarm from happening as a outcome of the saved mild on the sensor

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14W CLASS A AMPLIFIER CIRCUIT USING 2N3055 SCHEMATIC DIAGRAM

14W CLASS A AMPLIFIER CIRCUIT USING 2N3055 SCHEMATIC DIAGRAM

Many early amplifiers operated in Class A, but as output powers rose above 10W the problems of heat dissipation and power supply design caused most manufacturers to turn to the simpler, more efficient Class B arrangements and to put up with the resulting drop in perceived output quality. Why Class A ? Because , when biased to class A, the transistors are always turned on, always ready to respond instantaneously to an input signal. Class B and Class AB output stages require a microsecond or more to turn on. The Class A operation permits cleaner operation under the high-current slewing conditions that occur when transient audio signal are fed difficult loads. His amplifier is basically simple, as can be seen from the block diagram.

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Audio Booster Circuit

Small and portable unit, Can be built on a veroboard

The amplifiers gain is nominally 20 dB. Its frequency response is determined primarily by the value of just a few components-primarily C1 and R1. The values of the schematic diagram provide a response of ±3.0 dB from about 120 Hz to better than 20,000 Hz.Actually, the frequency response is ruler flat from about 170 Hz to well over 20,000 Hz; its the low end that deviates from a flat frequency response. 

The low ends roll-off is primarily a function of capacitor C1(since RIs resistive value is fixed). If C1s value is changed to 0.1 pF, the low ends comer frequency-the frequency at which the low-end roll-off starts-is reduced to about 70 Hz. If you need an even deeper low-end roll-off, change C1 to a 1.0 pF capacitor; if its an electrolytic type, make certain that its installed into the circuit with the correct polarity, with the positive terminal connected to Q1s base terminal.

Circuit Diagram:

 Audio Booster Circuit Diagram

Parts	Description
P1	100K
R1	47K
R2	470K
R3	10K
R4	560R
R5	270R
C1	0.1uF-25v
C2	3.3uF-25v
C3	470uF-25V
D1	5mm. Red Led
B1	9v Battery
J1	RCA Audio Input Socket
J2	RCA Audio Output Socket
S1	On-Off Switch

streampowers

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Easy Discrete Low Drop Regulator

This circuit was designed to ensure that an amplifier circuit containing a TDA1516Q would not exceed its maximum supply voltage when the load is small. This amplifier is used in a PC to increase the audio power somewhat. The PC power supply, however, created so much interference that an additional power supply was required.

Discrete Low-Drop Regulator Circuit Diagram

The power supply has its own power trans-former with a secondary voltage of 12 V AC. After rectification and filtering this results in a DC voltage of about 16 V. The regulator consists of a P-channel MOSFET SJ117, the gate of which is driven via a voltage divider connected to T2. The base of T2 is held at a constant voltage by LED D2, so that the volt-age across emitter resistor R2 is also constant and therefore carries a constant cur-rent. 

When the output voltage is higher than about 13.5 V, zener diode D1 will start to con-duct and supply part of the current through R2 — as a result the MOSFET will be turned on a little less. In this way there is a balance point, where the output voltage will be a little over 13.5 V (1.5 V across R2 plus the 12 V zener voltage). The regulator is capable of deliver-ing up to about 2 A — in any case it is a good idea to fit the MOSFET with a heatsink.

It is possible to add an optional potentiometer in series with the 12-V zener diode, which will allow a small amount of adjustment of the output voltage.The relay at the AC powerline input ensures that the power supply is only turned on when the PC is turned on. This relay is driven from a 4-way power supply connector from the PC. link

Author : Jac Hettema – Copyright: Elektor

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Hubbell Wiring Device Kellems 74093561 Conduit Grip

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How to Make a 200 Watt Transformerless Inverter Circuit

    A 12 V car battery can be used as the 12V source.
    Use the POT R1 to set the output frequency to50Hz.
    For the transformer get a 9-0-9 V , 10A step down transformer.But here the 9-0-9 V winding will be the primary and 220V winding will be the secondary.
    If you could not get a 10A rated transformer , don’t worry a 5A one will be just enough. But the allowed out put power will be reduced to 60W.
    Use a 10 A fuse in series with the battery as shown in circuit.
    Mount the IC on an IC holder.
    Remember,this circuit is nothing when compared to advanced PWM inverters.This is a low cost circuit meant for low scale applications.

Inverter Design Tips.

The maximum allowed output power of an inverter depends on two factors.The maximum current rating of the transformer primary and the current rating of the driving transistors.

For example ,to get a 100 Watt output using 12 V car battery the primary current will be ~8A ,(100/12) because P=VxI.So the primary of transformer must be rated above 8A.

Also here ,each final driver transistors must be rated above 4A. Here two will be conducting parallel in each half cycle, so I=8/2 = 4A .

source: circuitstoday.com

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Smart Trailing Socket

Mains sockets swaped routinely via a Control Socket, Up to 1000W changeed power

This circuit consists of a Trailing Socket (also called Extension or Distribution Socket) or identical software where two, three or more sockets (depending on the box dimensions and on constructors needs) will most probably be powered only when a current floats within the Control Socket. For example: if an electrical drill is hooked up to the Control Socket, the Switched Sockets will probably be powered every time the electric drill is running. In this case, a lamp may be related to a Switched Socket and will illuminate when the drill is operating. Another example: a desk lamp can be connected to the Control Socket and a PC, a Monitor and a Printer can be related to the Switched Sockets and will be running after the lamp is changeed on. Switching off the lamp, all the above talked about appliances will be routinely changeed off. A additional utility is the keep a watch on of a High Fidelity chain, plugging the Power Amplifier within the Control Socket and - for example - CD Player, Tape Recorder, and Tuner within the Switched Sockets.

Usually, trailing sockets are placed to the rear of the applyings, ceaselessly in places no longer simply reachable, so, although the socket has a change, it is much more uncomplicated to switch on and off the High Fidelity chain from the principle amplifier itself. The similar consideration is valid for pc-monitor-printer chains and so forth. Nevertheless, in this case, the utilization of a table lamp plugged in the Control Socket is nearly necessary, as defined beneath. In truth, this very sensitive circuit works fantastic when appliances having full breaking swapes like lamps, drills, most power amplifiers, old radios, outdated TV units, fanatics, nearly all electrical household appliances and so on. are plugged in the Control Socket. This is for the rationale thatse softwares have a switch that totally excludes the inner circuitry from the majors. Unfortunately, in modern devices like computers, displays, CD avid gamers, up to date radios and TV units (usually powered by means of interior \"switching\" supplies), the energy swap does now not totally isolate the interior circuitry from the primarys, as transient suppressors and different elements stay on circuit. This result ins an extraordinarily small present to waft throughout the sensing circuitry, however enough to set off the output Triac.

Therefore, the switched devices will remain at all times on, no matter if the keep watch over appliance is on or off. This could additionally occur when softwares connected to the primarys by approach of plug-in power supply adapters are used as keep a watch on appliances, due to their lack of a chiefs switch. In spite of this restrict, the circuit can additionally be nonetheless helpful, due to the excessive number and variety of tools allowing impeccable performance when they're plugged within the Control Socket.

Circuit diagram:

Smart Trailing Socket Circuit Diagram

Parts:
R1,R2_________100R 1/2W Resistors
C1____________100nF 630V Polyester Capacitor
D1 to D6_____1N5408 1000V 3A Diodes (See Notes)
D7__________TIC225M 600V 8A Sensitive Gate Triac (See Notes)
A industrial trailing socket to be modified or a self-made box with a few sockets.

Circuit operation:

Six back-to-back energy diodes are connected in series to the Control Socket. The current drawn via the instrument plugged into this socket when within the on state, flowing through the diode chain, lead tos a voltage drop of about 2V. This voltage, limited by way of R1, pressures the Gate of the Triac D7 which, in turn, will swap the output sockets. C1 and R2 type a so called \"Snubber network\", serving to to eliminate swaping transients generated with the help of inductive masses.

Notes:

• The circuit is small enough to be embedded into some sorts of commercial trailing sockets, or a box with a lot of sockets can additionally be made at will.
• The diode types advised in the Parts List for D1 to D6 will enable an appliance of up to about 500W power to be plugged within the Control Socket. Use BY550-800 diodes for up to 800 - 1000W.
• For much less hectic home equipment, 1N4007 diodes will permit up to 200W power.
• The Triac type instructed in the Parts List for D7 will allow a complete power to be had to the Switched Sockets of greater than 1000W. If you wish to force a lot of more than 500W complete, please use a suitable heatsink.
• Wanting to power less powerful loads, you can use for D7 a TIC216M (up to 800 - 1000W) or a TIC206M (up to 500 - 600W).
• Warning! The device is attached to 230Vac majors, so some sections within the circuit board are subjected to lethal potential! Avoid touching the circuit when the primarys twine is plugged in!
  

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6 to 15V DC to DC Converter

A very efficient 6V to 15V DC to DC converter using LM2585 is shown here. LM2585 is a monolithic integrated voltage converter IC that can be used in various applications like flyback converters, boost converters, forward converters, multiple output converters etc. The circuit requires minimum number of external components and the IC can source up to 3A output current.

Circuit diagram :

6 to 15V DC to DC Converter Circuit Diagram

Here the IC is wired as a boost converter where resistors R1 and R2 are used to set the output voltage .The junction of R1 and R2 is connected to the feedback pin of IC1. Capacitor C4 is the input filter while capacitor C1 the filter for output. Network comprising of resistor R1 and capacitor C2 is meant for frequency compensation. Inductor L1 stores the energy for acquiring boost conversion.

Notes:    

• Assemble the circuit on a good quality PCB.
• LM2585 requires a heatsink.
• Output voltage is according to the equation Vout =( (R1/R2)+1) x 1.23.
• Capacitors other than C4 and C1 are ceramic capacitors.
• Maximum output current LM2585 can source is 3A. 

Source : Circuitstoday

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3 VOLT 6 VOLT MINI AUDIO AMPLIFIER SCHEMATIC DIAGRAM

3 VOLT - 6 VOLT MINI AUDIO AMPLIFIER SCHEMATIC DIAGRAM



The potentiometer circuit can be used to control volume. Capacitor C1 and C2 are designed to filter supplyvoltage If the battery separator is used as operations offer source.For using batteries C1 and C2 are not required.



IC TDA7052 is a mono output amplifier in 8-comng Head DI package (DIP). The device is designed primarily for battery-operated portable audio circuits. Features include TDA 7052, no external components needed, no switch-on or switch-off button sounds great overall stability and very low power consumption (quiescent current of 4 mA), low THD, it is not necessary any cooler and short-circuit proof.



Profit TDA 7052 is set internally at 40 dB. . Compensate for the reduction of output power due to low voltage TDA7052 uses Bridge-Tied-Load principle

(BTL), which can provide power about 1 to 2 W RMS (THD = 10%), 8 ohm load to the power supply 6 V.

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Automatic TV Lighting Switch

The author is the happy owner of a television set with built-in Ambilight lighting in the living room. Unfortunately, the television set in  the bedroom lacks this feature. To make up for this, the author attached a small lamp to the wall to provide background lighting, This makes  watching television a good deal more enjoyable, but it ’s  not the ideal solution. Although the TV set can be  switched off with the remote  control, you still have to get out of bed to switch off the lamp.

Circuit diagram :

Automatic TV Lighting Switch Circuit Diagram

Consequently, the author devised this automatic lighting switch that switches the background light on and off along with the T V set. The entire circuit is fitted in series with the mains cable of the TV set, so there’s no need to tinker with the set. It works as follows: R1 senses  the current drawn by the TV  set. It has a maximum value  of 50 mA in standby mode,  rising  to around   500 m A  when  the  set  is  operating. The voltage across R1 is limited by D5 during negative  half- cycles  and  by  D1– D4  during positive half-cycles.  T he  voltage  across  these  four diodes charges capacitor C1 via D6 during positive  half-cycles. This voltage drives the internal LED of solid-state switch TRI1 via R2, which causes the internal triac to conduct and pass the mains voltage to the lamp.   Diode D7 is not absolutely necessary, but  it is recommended because the LED in the  solid-state switch is not especially robust  and cannot handle reverse polarisation. Fuse  F1 protects the solid-state switch against  overloads. T he  value  of  use d  here  (10 Ω)  for  resistor R1 works nicely with an 82-cm (32 inch)  LCD screen.

With smaller sets having lower  power consumption, the value of R1 can be  increased to 22 or 33 Ω, in which case you  should use a 3-watt type. Avoid using an  excessively high resistance, as otherwise TRI1 will switch on when the TV set is in standby mode.  Some TV sets have a half-wave rectifier in the  power supply, which places an unbalanced  load on the AC power outlet. If the set only  draws current on negative half-cycles, the cir-cuit won’t work properly. In countries with  reversible AC power plugs you can correct  the problem by simply reversing the plug. Compared with normal triacs, optically cou-pled solid-state relays have poor resistance  to high switch-on currents (inrush currents).

For this reason, you should be careful with  older-model TV sets with picture tubes (due  to demagnetisation circuits). If the relay fails,  it usually fails shorted, with the result that the TV background light remains on all the time. If you build this circuit on a piece of perf-board, you must remove all the copper next  to conductors and components carrying  mains voltage. Use PCB terminal blocks with a spacing of 7.5 mm. This way the separation between the connections on the solder  side will also be 3 mm. If you fit the entire  arrangement as a Class II device, all parts of  the circuit at mains potential must have a  separation of at least 6 mm from any metal  enclosure or electrically conductive exterior  parts that can be touched. 

 

 

 

http://streampowers.blogspot.com/2012/06/automatic-tv-lighting-switch_11.html 

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Pump it up Mp3 Booster

MP3 players are all the rage these days. The smaller ones in memory-stick format are particularly easy to take with you; your very own ‘personal sound system’ on the move! It’s when you want others to share your taste in music that you find these players to have a lack of power. You can get round this problem with the help of the MP3 booster, a small amplifier that can be used to connect your MP3 player directly to your Hi-Fi. When you next invite your friends to a party you can ask them to bring their ‘personal music’ as well as the usual drinks!

But first we have to build this booster! The small battery-powered players have an output signal that is more than sufficient to drive a set of 32 Ohm headphones. You’ll often find that with an output of 1mW the sound pressure level (SPL) produced can reach up to 90 dB. This would be sufficient to cause permanent damage to your hearing after only one hour! The maximum output voltage will then be around 200mV. This, however, is insufficient to fully drive a power amplifier. For this you’ll need an extra circuit that boosts the output voltage.

Power amps usually require 1 V for maximum output, hence the signal has to be amplified by a factor of five. We will also have to bear in mind that quieter recordings may need to be amplified even more. We’ve used a simple method here to select the gain, which avoids the use of potentiometers. After all, the MP3 player already has its own volume control. We decided to have two gain settings on the booster, one of three times and the other ten times. Amplifiers IC1A and IC1B (for the right and left channels) are housed in a single package, a TS922IN.

The output signal of the MP3 player is fed via a stereo cable and socket K1 to the inputs of the amplifiers. The gain depends on the relationship between resistors R2 and R1 (R6 and R5 for the other channel) and is equal to ten times. When you add jumper JP1 (JP2), resistor R3 (R7) will be connected in parallel with the negative feedback resistor R1 (R6), which causes the gain to be reduced to about three. When you start using the booster you can decide which gain setting works best for you.

Circuit diagram:

MP3 Booster Circuit Diagram

Resistor R4 (R8) takes the amplified MP3 signal to the output socket K2 (K3). A cable then connects these phono sockets to the input of your power amplifier. The resistors connected in series with the output (R4 and R8) are there to keep the booster stable when a long cable is connected to its output. Cables have an unwelcome, parasitic capacitance. This capacitive effect could (due to phase shifts of the signal) affect the negative feedback of the booster in such a way that a positive feed back occurs, with the result that the booster oscillates and possibly damages the power amplifier!

The resistors (R4 and R8) effectively isolate the output of the booster from the parasitic capacitance of the output cable. They also protect the booster outputs from short circuits. We’ve used a TS922IN opamp in this booster because it can operate at very low supply voltages (the maximum is only 12 V!), but can still output a reasonable current (80 mA max.). For the supply we’ve used rechargeable batteries (e.g. NiCd or NiMH cells) so that we don’t need a mains supply.

To keep the number of cells required as small as possible, we’ve chosen a supply voltage of 5 volt; this can be supplied by four rechargeable batteries. It is also possible to use four ordinary, non-rechargeable batteries; it’s true that the supply voltage then becomes a bit higher (6 Volts), but that won’t cause any harm. Since we’ve used a symmetrical supply for the booster (2 x 2 batteries), it will be easiest if you use two separate battery holders, each with two AA cells. The two holders are connected in series.

Make sure that the batteries are connected the right way round; the positive of one always has to be connected to the negative of the next. This also applies to the connection between the two battery holders. S1A/B is a double pole switch, which is used to turn both halves of the battery supply on or off simultaneously. If you can’t find the (dual) opamp we’ve used (or an equivalent), you could always use standard opamps such as the NE5532, TL082 or TL072. These do need a higher supply voltage to operate properly. In these cases you should use two 9 V batteries and replace resistor R9 with a 15 kΩ one.

Do take care when you connect the circuit to your power amplifier because the output signal can be a lot larger and you could overload the power amplifier. (Although you’re more likely to damage the loudspeakers, rather than the amplifier!) (Please note that these two 9 V batteries can’t be used as a supply for the TS922IN!) In our circuit we’ve used a stereo jack socket for the input and phono sockets for the output because these are the most compatible with MP3 players and power amplifiers respectively. If you wanted to, you could solder shielded cables directly to the circuit instead, with the correct plugs on the ends. You’ll never find yourself without the correct connection leads in that case!

 

 

 

Streampowers

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How to Make a Simplest Compact 1 Watt LED Driver Circuit at 220V 110V Mains Voltage

Circuit diagram.

Seetharaman’s words about the circuit: I am sending you a table lamp made from defunct energy saver lamp with broken tubes. CFL converted into LED lamp. Most of the components will be available in ones scrap box. Few components available in the CFL PCB also can be used.

Procedure
1. Carefully remove the broken glasses
2. Open the assembly carefully
3. Remove electronics and discard
4. Assemble the circuit in dot matrix PC or on a 1mm laminate sheet.
5. Cut a round laminate sheet with (scissor)
6. Mark the position of the 6 round holes on the sheet
7. Drill the holes to suit the LEDs to flush fit in the six holes
8. Use a dab of adhesive to keep the LED assembly in position
9. Close the assembly
10. Ensure the internal wiring does not touch each other
11. Now test on 230Volt AC
Your nice compact table lamp / puja room lamp / passage lamp is ready for use.

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Lambda Probe Readout For Carburettor Tuning

A lambda probe (or oxygen sensor) can be found on the exhaust system of most cars running on unleaded fuel. Having reached its normal operating temperature (of about 600 degrees Celsius!) the lambda probe supplies an output voltage proportional to the amount of residual oxygen measured in the exhaust gas.

This information is indicative of, among others, the air/fuel ratio supplied by the carburetor(s) and hence the combustion efficiency. In modern car (and motorcycle) engines, this information is used to (electronically) adjust engine parameters like ignition timing and fuel injection. The indicator described here is intended for permanent installation on a motorcycle of which the air/fuel ratio needed to be watched, with the obvious aim engine power tuning after fitting a different set of carburetors. Apart from this obvious technical use the unit’s bright LEDs will no doubt attract the attention of curious motorcyclists.

At the local junkyard a single-wire lambda probe may be salvaged from a wrecked car. Once a suitable nut has been found, the probe can screwed into the exhaust pipe of the motorcycle, at about 30 cm from the cylinders.  Since we’re talking of welding and drilling in an expensive (chrome-plated) exhaust pipe, you may find that actually fitting the probe is best left to specialists!  The starting point for the design of a suitable electronic indicator is that in the noble art of carburetor tuning an air/fuel ratio of 14.7 to 1 is generally considered ‘perfect’, the range covering 16.2 to 1 (‘lean’) to 11.7 to 1 (‘rich’). The perfect ratio typically corresponds to a probe output voltage of 0.45 V. 

 Referring to the circuit diagram, that is the input level at which 5 of the 10 LEDs will light, including the green one, D5. If one of the red LEDs lights, the mixture is definitely too rich. Note that in general it is better to have a mixture that is a little to rich than one that’s on the lean side, hence a yellow LED lights between the green LED and the first red one. Also note that the engine needs to be at its normal operating temperature before a meaningful indication is obtained.

 

 

 

streamcircuits

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12KV High Voltage Generator

The hobby circuit below uses an unusual method to generate about 12,000 volts with about 5uA of current. Two SCRs form two pulse generator circuits. The two SCRs discharge a 0.047uF a 400v capacitor through a xenon lamp trigger coil at 120 times a second.

 

The high voltage pulses produced at the secondary of the trigger coil are rectified using two 6KV damper diodes. The voltage doubler circuit at the secondary of the trigger coil charges up two high voltage disc capacitors up to about 12KV. Although this circuit can’t produce a lot of current be very careful with it. A 12KV spark can jump about 0.75 of an inch so the electronic circuit needs to be carefully wired with lots of space between components.

 

 

 

Source by : Streampowers

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150W BRIBGE AMPLIFIER WITH TDA 7294 CIRCUIT DIAGRAM

150W BRIBGE AMPLIFIER WITH TDA 7294 CIRCUIT DIAGRAM

As you can see, there are provisions to use TDA7294 well. This circuit is almost identical, but a specification higher. There are links on the board to connect contacts 1 and 5 (it should not be connected to the TDA727). Use TDA7294, fees can run bridged (BTL or bridge tied load) to about 150 W at 8 ohms. I think P87B be used to provide phase signal is necessary for BTL operation. Although it is common to see AMP as a reversal, there is a very low resistance at first, and may lead to unacceptable pressures and possible distortion. P87B be managed separately by each amplifier, and the best way to control the amplifiers.While parallel operation is often recommended, I strongly recommend that you run the amps in parallel. There are very strict requirements for greater tolerance for parallel operation – usually amplifiers must correspond to 0.1% or more for all audio traffic and beyond. A very low output resistance of members, even inconsistencies 100mV (instantly, any voltage and frequency) can cause large amounts of current flowing through the circuits. Although 0.1O resistors are usually offered, inconsistencies 100mV voltage (0.15% at the peak voltage 60V) 0.5A cause a circulating current. This leads to overheating and protection of anger involved.

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14 W AUDIO AMPLIFIER TDA2030 CIRCUIT SCHEMATIC DIAGRAM

14 W AUDIO AMPLIFIER TDA2030 CIRCUIT SCHEMATIC DIAGRAM

Resistors should be at least 1/4W types with 1% tolerance recommended. I used 0.6W 1% metal film resistors and they work well. Capacitors I used were electrolytic cans for C2, C5 and C6. At the time of building, I did not have enough 100uF caps so I used 220uF caps instead, this will not cause trouble, unless you use caps that are smaller than 100uF for C5 and C6.



C1 can be electrolytic, I used a tantalum myself (dont ask why, since they are actually more expensive). Some readers may want to use a polyester capacitor for the input (C1), this would work too but I am not sure whether any benefit will arise from the extra expense. Other capacitors (bypass caps C3 and C4. and C7) are ideally polyester caps. Mylar may be used but I prefer polyester caps and they are not expensive unless you get large values.



The values of R5 and C8 are worked out from the equations in the datasheet, but I used 1.8k ohm for R5 and 220pF for C8 and they work fine. Diodes should be 1N4001 or similar (make sure you solder them in the right way round).



A good heatsink is important and this should be a large size with good thermal conductivity. When you operate the TDA2030 from the (recommended) split rail power supply, you must insulate the device from the heatsink using a mica washer or similar. With single rail supply, this is not needed.

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