Tag Archives: audio circuit

Easy Loudspeaker Circuit For Telephone

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This below circuit is a easy handsfree telephone receiver system. This doesn’t have dialing circuit so, it’s not a total phone replacement circuit, but it’s just only a loudspeaker system (i.e, phone receiver,not dialer). This is a easy circuit with all parts easily available, and without any complex I.C. It… Read more »

Luggage Security System

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Guaranteed to get the TSA’s attention While traveling by a train or bus, we generally lock our luggage using a chain-and-lock arrangement. But, still we are under tension, apprehending that somebody may cut the chain and steal our luggage. Here is a simple circuit to alarm you when somebody tries… Read more »

Clap Sensitive On-Off Relay

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3V Battery operated, Small portable unit This circuit was intended to activate a relay by means of a hand clap. Further claps will turn-off the relay. An interesting and unusual feature of this project is the 3V battery operation. The circuit’s sensitivity was deliberately reduced, in order to avoid unpredictable… Read more »

Peak Indicator

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Small, portable and experimental circuit, Simple unit A simple circuit, peak indicator of tops of musical signal. Each time where the level of signal exceeds the level + 4dB, turns on led D1. It is useful in each channel of console of sound, in final amplifiers or in that other… Read more »

Subwoofer Lowpass Filter using uA741 Single Op-Amp Ic

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This is the simplest Sub woofer Low Pass filter Circuit using uA741 single op amp ic. The circuit is very low cost with respect to their work. The cut off frequency of this circuit is 25Hz to 80Hz maximum. Using this circuit , you can easily design a 2.1 Sub-woofer… Read more »

Aviation Intercom

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Before its move offshore, I was lucky enough to be involved in developing the avionics system for the Flightship Ground Effect FS8 craft (see http://www.pacificseaflight.com/craft.shtml). Although officially classed as a boat, it has wings and can travel at 180km/h some three metres above the water. The communications system was adapted… Read more »

Pre-Amp + Tone Control with TDA1524A

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This is a low noise and distortion pre-amplifier and tone control circuit in one module. Using a special IC TDA1524A, this simple circuit is easy to build and will drive most of power amplifier. Schematic diagram: Component: Resistors: R1, R2__________________ 220R R3, R4__________________ 4K7 R5______________________ 2K2 R6______________________ 1K Capacitors: C1,… Read more »