6V Gel Cell Battery Charger

The following scheme diagram is the battery charger circuit for 6V Gel Cell battery type only. Components List: R1 = 22 ohm, 1W R2 = 270 ohm R3 = 220 ohm *R4 = 715 ohm, 1% *R5 = 3.57K, 1% *R6 = 1.40K, 1% *R7 = 1.47K, 1% C1 = 0.1uF, ceramic C2 = 0.1uF,… Read More »

NiCAD Battery Charger with Current and Voltage Limiting

The following diagram is the schematic diagram of Ni-CAD battery charger circuit which featured with current and voltage limiting to keep the battery lifetime. The lamp L1 will be light brightly and the LED will be out when the battery is low and battery charging in progress, but the LED is very bright and the… Read More »

ACTOR : Active Tone Control

The following diagram is the schematic diagram of Active Tone Control circuit, or we often call this circuit as “ACTOR”. The circuit is quite simple, easy build and inexpensive, you can build this circuit with minimum / low cost. Active Tone Control or ACTOR is an active electronic audio circuit that serves to increase the… Read More »

Dynamic Mic Compressor

The circuit below is a Dynamic Mic Compressor circuit which is simple, easy to built, inexpensive but the results are quite satisfactory. Audio output sounded outstanding. The principle of this circuit is very simple, the first transistor is used as microphone pre-amplifier. Then a second transistor used as a buffer. And the third transistor is… Read More »

4 Band Equalizer

The following scheme diagram is the four 4 band equalizer circuit. Equalizer device is generally used to improve the fidelity of sound, to emphasize certain instruments, to remove undesired noises, or to create completely new and different timbres. This circuit operated with 12VDC symmetrical / dual polarity power supply. Power supply circuit provided on above… Read More »

Passive Surround

This is the scheme diagram of passive surround circuit. Passive surround doesn’t need any active components and power supply to make the circuit works. The circuit just need the combination of resistors and electrolytic capacitors. Circuit Notes: This passive surround circuit MUST be connected after power amplifier module. Use full range type of loudspeaker. Do… Read More »