This circuit is from an American 1967 documentation and can be implemented with modern equivalent transistors. The circuit serves as a Q multiplier.
This circuit consists of a traditional version amplifier with complementary output transistors...
September 2017 - Microchip's MCP6411 operational amplifiers for frequencies up to 1 MHz are in...
If the input voltage falls below 12 V the LED glows up. Other voltages can be monitored by...