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 with only one transistor was obtained in an old English documentation and can be...
This circuit uses a transistor as noise source and a 741 IC as amplifier, sourcing a high...
This circuit uses an LED (called SSL) to regulate current in a configuration with complementary...