This gas sensor circuit was found in July 1976 Radio Electronics magazine. The TGS sensor was a common type at the time. Note the power supply to the circuit.
When this circuit is activated the LED flashes for a moment indicating that the function has been...
This is the basic configuration for using a moving bar indicator or bargraph using the LM3914...
This circuit was found in old documentation. Transistors can be general purpose JFET types and the...