Battery Voltage Monitor circuits
The simple low voltage tester circuit using LM339,can use Battery voltage monitor for voltage sources that problems, by LED display and alarm sound. Read more
Meters & Detectors
Continuity tester circuit with Buzzer and LED
Create continuity tester circuit with buzzer and LED for check solder joint defects, not kill components on PCB, as probe gives tiny current and voltage. Read more
LED VU Meter circuits using transistors, 5 to 20, 40 LED
See LED VU meter using transistor is analog circuit to show the level of power audio signal. You can build 5 LED to 20 LED display with PCB. Read more
Simple Light Detector Alarm with solar sensor
This is Simple Solar light alarm circuit with the special edition, that improve this circuit whole new to higher efficiency. use solar cell instead of LDR Read more
Food & Water Salinity Tester Meter circuit
SEE a simple salinometer or salinity tester in food and water. Good for health. Using LM324 and few parts and LED display easily use, with 9V batts Read more