This circuit was found in an American 1980s documentation. It analyzes the exhaust gas of a vehicle using a special sensor. The indicator is a milliamperimeter.
The integrated circuit of this amplifier is not very common today. The output transistors can be...
This circuit is from a1970 documentation. R1 may have 10k and P1 47k. The transistors can be BC558...
This circuit is from a 1977 documentation. It is powered by the power supply of the circuit under...