This is another stereo / dual power amplifier circuit with power IC KA series. This amplifier delivers dual power output (stereo) at 1.2W for each channel. General The KA2214 is a monolithic integrated dual audio power amplifier in a 14-pin plastic dual in line package. It is designed portable audio sets.
This is a simple audio pre-amplifier circuit using single transistor 2N3904. This easy circuit provides good gain to weak audio signals such as electret microphone. Use it in front of an RF oscillator to make an RF transmitter that’s very sensitive to sound. Power supply used for this circuit is wide range from 3VDC to… Read More »
This is 2x1W stereo amplifier circuit based on single IC KA2209. IC KA2209 is an equivalent IC to the TDA2822, you can use TDA2822 if you can’t find KA2209. It is ideal for battery powered operation since the supply required for this circuit is 2V to 9VDC. Power output depends critically on speaker resistance &… Read More »
Here the SW transmitter circuit based on IC BEL1895. This particular transmitter circuit works in shortwave HF band (6 MHz to 15 MHz), and can be applied for shortrange communication and for educational purposes. The circuit is composed of a mic amplifier circuit, a variable frequency oscillator, and modulation amplifier stages. Transistor T1 (BF195) is… Read More »
This a two station intercom. It uses two wires to run between each intercom unit. Each is self contained with its own battery, speaker, microphone and amplifier circuit. An LM386 audio power amplifier is used. It is widely available, used a minimum of external parts and is well suited to battery operation. It will give… Read More »