Schematics of delabs

This is a LED Analog Meter, This can be used as a Resistance Meter and Low Impedance Voltmeter for Battery Levels. Resistance measurement Current Source To measure battery voltage, the R5-R12-R17 etc. part of the Reference Resistor Divider Network can… more »

This circuit uses a LM339, a quad comparator. LM339 can work on single or dual supplies, it has a open collector output that can drive 15mA, low power consumption. The circuit is an untested design but it should work. Mains Voltage and Power… more »