This circuit was found in the December 1992 Radio Electronis magazine. R2 is an NTC, there is a MOV protector or NTC thermistor. The current depends on the thermistor used.
The great advantage of the circuit shown in the figure is the fact that its frequency is...
Found in American documentation from 1969, this circuit produces a pulsating waveform being...
Found in an old Elektor, this circuit uses two 7-segment displays to indicate the volume of an...