Using one unijunction transistor and two bipolar transistors, this circuit generates a signal from 25 Hz to 3 kHz. The circuit is from Electronics Now magazine, January 0, 1994.
The CMOS TLC555 [equivalent to the bipolar 555] can be used as a monostable in the configuration...
This very simple circuit must use coal microphones of the type found in very old equipment. The...
This circuit was found in an English publication from the 70's. The circuit requires symmetrical...