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 circuit is from 2002 documentation. It injects a signal into a power amplifier and measures the...
The integrated circuit used in this project is not the most common. The use of a crystal...
This configuration was found in an American publication from the 90s. Operators admit equivalents just...