13.8 Volt 20 A Transformerless Power Supply

Do you need high current power supply without heavy and expensive transformer? Then, this circuit would be great choice for you. This 13.8 Volt 20 A regulated transformerless power supply. 20A transformer is very-very expensive, large in size and very heavy in weight.

0-30V Stabilized Variable Power Supply with Current Control

This is high quality 0-30v stabilized variable power supply circuit diagram. You will able to adjust the output voltage from 0 volt up to 30 volt DC. You also able to adjust the current output value from 0.002 A to 3 A. This variable power supply incorporates an electronic output current limiter that effectively controls… Read More »

Stereo Tone Control with Line In + Microphone Mixer

This is an active stereo tone control circuit using very well known op-amp IC of TL072. The circuit include mic pre-amp and mixer control. In this design, we have two inputs: one for line (stereo), one for microphone and has control of the three audio frequency (high/treble, medium and low/bass). It also provide balance control… Read More »

Bass Guitar Preamp Pedal

Here is the circuit diagram and PCB design for relatively low cost DIY bass guitar preamp pedal uses FET K117 or equivalent. There is a bit difficult to build this kind circuit project, it’s require a good knowledge in electronics. This preamp has several features for the bass guitar instrument such as attenuator, low cut, mid… Read More »

Small Sound Amplifier for Ears (Hearing Aid)

This is the simple project of small sound amplifier for ears or often called hearing aid device or hearing loss amplifier. This circuit was already tested on some patients and give significant improvement in the hearing ability to the patients. It consumes a very small amount of power within the range of 10 milliwatts. Furthermore,… Read More »

Active Speaker Protector

This is a simple active speaker protector circuit which has a very important use, expecially to protect the loudspeakers of a audio system. It prevent the speaker from noise sound when we turn on the power amplifier. The circuit drives the speakers after 3 to 10 seconds so that the source of the same stabilizes… Read More »