Found in a 1980s German publication, this circuit tests batteries by type. The circuit is based on a range of LEDs of different colors and is given a table with indications for various voltage ranges.
This simple two position dimmer is suitable for low wattage incandescent lamps. The diode can be...
This circuit is from a 1967 publication. The potentiometer above 4M7 is the critical component. The...
The inverter shown in the figure can generate voltages in the range of 80 to 600 volts depending on the...