Balance Indicator for Symmetric Power Supply

Balance indicator for power supply show if a symmetric power supply is really symmetric or not. With two comparator pairs from a LM339N quad comparator we can make a such indicator. One pair drives the red warn LED3 and the … Continue reading
Two Methods for Push Button Controlled Power Switch

On these two following circuits, we can latch on the SCR (and thereby the lamp) by momentarily closing S1, thereby feeding gate drive to the SC via R1. The gate is tied to the cathode via R2 to improve circuit … Continue reading
Portable Calibrator: Stable 10V Reference

A stable voltage source is needed in many calibration process. Most electronic devices are affected by its surrounding temperature. To control all the components temperature by manipulating the surrounding temperature is not easy, but fortunately we can control only the … Continue reading
Long Interval RC Timer Using Op-Amp

With the help of high gain high impedance operational amplifier, we can build a long time delay with resistor-capacitor (RC) circuit since it allow high resistance resistors to be used. We can calculate the time (t) using the following formula; … Continue reading