60W AF Amplifier With STK-0060II

This is a 60W AF power amplifier based on single Sanyo integrated circuit STK-0060II. This circuit delivers 60W mono/single channel audio output. For stereo channel, you may build two identical circuits and of course doubled the power supply current (use 5A transformer for stereo application). The amplifier circuit uses symmetrical (dual polarity) power suppy. Recommended… Read More »

Digital Variable Resistor / Potensiometer DS1669

The DS1669 is an electronic digital rheostat manufactured by Dallas Semiconductor. This component has a function similar to digital variable resistor/potensiometer which can be operated by push the buttons. You can adjust the audio volume, LCD contrast, frequency, etc. by using two buttons instead of a common potentiometer/trimpot. This circuit explains how we do it… Read More »

Ultrasonic Distance Detector / Sonar Ranging System

This is the ultrasonic distance detector or sonar ranging system which can be used for general purpose. There are kit version available on the market, but of course the price is 3x more expensive than if you build your own sonar ranging system. Some application may use this circuit such as robot applications, body height… 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 »

Electronic Horn

This is an easy, low cost and easy built circuit of an electronic horn which is designed close to quadruple op-amp IC LM3900 (IC1). IC LM3900 has four independent operational-amplifiers (A1 through A4) having a large output voltage swing. It is able to operate at up to 32V DC. The 1st op-amp (A1) is designed… Read More »