This is a 12VDC to 9VDC converter circuit. You may use this DC to DC stepdown converter circuit if you have fixed 12V power supply / battery, but you need 9V power supply for your electronic devices. Scheme Diagram: Components List: R1________ 560 ohm, resistor C1________ 1000uF/16V, Electrolytic capacitor C2________ 100uF/16V, Electrolytic capacitor C3________ 330nF,… Read More »
This is a dual regulated and stabilized power supply, usually used to supply amplifier circuit, it also known as split powersupply. There are 3 output that are (+) voltage, (0) Ground (normal), and (-) voltage. The current output max about 0.3-0.5 A. For higher current output, power transistor is needed. Please take a note that… Read More »
If you’re interested in RF circuit, then you should know about this basic RF oscillator. This basic RF oscillator circuit is easy to build and the components are not critical. Most of them can be found in your junk parts box. The circuit operated with 9VDC power supply. The L1 antenna col can be made… Read More »
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 »