This high quality circuit with complementary symmetry was found in an Electronics World of 1966. It can be made with modern transistors like the BD or TIP series.
This circuit that uses only transistors indicates when the voltage in the circuit has the voltage...
This circuit was found in an American 80's documentation. However, it can be implemented with...
This circuit is from an old American publication. The indicated transistor is oversized as the 15 V...