1Hz Clock Generator with Chip On Board (COB)

This is the 1Hz clock generator circuit with Chip On Board (COB). Commonly, the circuits to produce 1Hz clock for digital clock and counter circuits applications implement ICs in conjunction with a crystal and trimmer capacitors, etc. Even so, equivalent or improved accuracy could be obtained working with a chip-on-board (COB) device found inside a… Read More »

100W Power Amplifier Based IC TDA7294

This is a very interesting circuit design to assemble. There are 4in1 amplifier module in a circuit board. 100W power amplifier using the TDA7294, for the VU meter uses IC LM3914. The tone control preamp uses the well-known IC 4558. The symmetrical power supply module also included in the PCB.

200W Power Amplifier Using Transistor

This is a 200W power amplifier circuit project. The circuit features high power, good definition and very low noise. It delivers about 200 watts in 4 ohms loudspeaker: a 4 ohm speaker or two pieces of 8 ohm speakers in parallel. This 200W power amplifier using the complementary transistors of 2SC5200 and 2SA1943 as the… Read More »

CD/DVD/Bluray-Disk Drives Troubleshooting and Repair Tutorial

This is the CD Drives troubleshooting and repair tutorial for your electronic service reference. It should be work and also largely relevant for DVD/HD DVD/Blu-ray equipment. This document was developed specifically for the troubleshooting and repair of the CD players in component stereo systems, compact stereos, boomboxes, car units and portables, as well as CDROM… Read More »

1 – 9V Variable Desktop Power Supply

Here the variable desktop power supply which will convert a high input voltage (12V) from the SMPS / PSU of a desktop computer into small output voltage (1.25 to 9 volts). This converter will be very beneficial for electronics hobbyists. An adjustable three-pin voltage regulator chip LM317T (IC1) is applied right here to deliver the… Read More »

Shutter Guard

This is the shutter guard circuit which has sensitive vibration sensor, piezo-sensor. This circuit is specifically designed for outlets to defend towards theft. It can recognize any mechanical or acoustic vibration in its area when somebody attempts to break the shutter and instantly turn on a lamp and sound an alert alarm. A 15-minute time… Read More »