Found in a 1967 EEE, this circuit uses the signal from the alternating current power grid to produce pulses from a Unijunction. The circuit is directly excited by the mains voltage.
This 1995 documentation circuit detects when an extension on a phone line is active. Adjustment of the...
In this circuit we have the use of a phototransistor of any type. The 47k resistor can eventually be...
The CMOS TLC555 [equivalent to the bipolar 555] can be used as a monostable in the configuration...