This circuit was found in documentation from the 1970s. However, it can be implemented with modern transistors such as 2N2222 for Q1 and BF494 for Q2. The crystal depends on the desired frequency.
This simple lie detector was found in Popular Electronics. Transistors are commonly used. The...
This circuit, using a unijunction transistor (UJT), converts a voltage applied to the input in a...
August 2017 - Texas Instruments' new integrated circuit BQ25872, a 7-A keyed battery charger with...