This circuit was found in the May 1984 issue of Radio Electronics magazine. It analyzes the exhaust gases emitted by a car. The circuit uses a special gas sensor from that time.
The frequency depends on the coil and is not found in the original documentation but should be...
This is a device for those who need to show that they know how to use digital electronics but have...
Using an operational amplifier with FET, this circuit from a 1977 publication can generate...