This circuit was obtained in a 90s EDN. The components used are from that time. The voltage obtained is negative for supplying LCDs.
This circuit was found in Electronics Handbook, Vol XIII 1993 and consists of a simple direction...
This circuit works only with carbon microphones, due its low impedance. The speaker should be good or...
This is the normal circuit of a relaxation oscillator using an unijunction transistor such as the...