Lamp flasher using LM317

john April 7, 2010 7 Comments
Description. Here is a very useful lamp flasher circuit using the famous adjustable voltage regulator IC LM317T. LM317 can source up to 1A of current and so up to 12W lamps can be used with this flasher. Such a...
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Single transistor audio mixer.

john April 7, 2010 3 Comments
Description. Many audio mixer circuits have been published here. But I think, this one is the simplest of them. This very simple audio mixer circuit uses only one transistor. The base emitter junction of the transistor is biased by...
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Lamp flasher using LM395

john April 7, 2010 No Comments
Description. This powerful lamp flasher circuit is ideal for use in automobiles. The circuit is based on IC LM395 (also known as super transistor) which is a very powerful integrated monolithic power transistor with features such as thermal overload...
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Two transistor siren

john April 7, 2010 9 Comments
Description. Here is the circuit diagram of a simple two transistor alarm circuit that can be operated from a 9V PP3 battery. Here the two transistors are wired to form an oscillator whose frequency increases when switch S2 is...
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Police siren

john April 7, 2010 14 Comments
Description. The circuit given here produces an alarm similar to the police siren. When you press the push button switch S2 capacitor C1 will charge and this will make the transistor Q1 to ON slowly. When the switch S1...
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Simple 10W audio amplifier

john November 2, 2011 11 Comments
Description. The circuit given below is of a simple audio amplifier that can deliver 12W to an 8 Ohm speaker. Op amp IC TL081 is used as the preamplifier here. Actually any opamp with matching power supply ratings can...
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Three transistor audio amplifier

john April 7, 2010 50 Comments
Description. This is the circuit diagram of a simple three transistor audio amplifier that can deliver around 100mW power to a 25 Ohm speaker. The diodes D1 and D2 provides a constant bias voltage for the transistors Q1 and...
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Whistle to beep circuit

john April 7, 2010 8 Comments
Description. This simple circuit produces a beeping sound that lasts for around 3 seconds whenever you make a whistle. The CMOS Hex inverter CD4049 is the heart of this circuit. Out of the six inverters in CD4049, U1a is...
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24W amplifier using TDA1516

john April 7, 2010 18 Comments
Description. Here is the circuit diagram of a simple 24W mono amplifier using IC TDA1516.The TDA1516 is an integrated class B power amplifier in a 13 pin SIL package. The IC has many useful features such as short circuit...
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Car battery charger

john April 7, 2010 53 Comments
Description. Given below, is a very simple circuit that can be used for charging car batteries. In this circuit there is facility for monitoring the charging current and voltage. The circuit is based on the IC MC78T12ABT from Freescale.The...
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