This circuit was found in a 90s Popular Electronics. The circuit operates in the range determined by L1. The integrated circuit used is uncommon today.
This circuit, from the 1977 GE semiconductor manual, uses a unijunction transistor beyond the...
This circuit, when connected to the 110 V power grid makes it possible to test capacitors with...
This circuit was found in a Texas Instruments handbook about operational amplifier. It has a very...