We found this circuit in a 1991 Hobbyst Electronics. The circuit makes use of an unusual transducer today. It is a piezoelectric buzzer that can eventually be replaced by an equivalent configuration.
This simple timer based on unijunction and SCR transistors is from 1995 documentation. The maximum...
This configuration with complementary transistors causes an LED to flash at a frequency that is...
An interesting application that can be implemented with the LM139 is the pulse width modulator. This is...