We found this circuit in a Motorola manual. The circuit has the capacitor charging at 15 to 30 V, then discharging through the coil and generating a voltage that reaches 500 V for the spark plugs.
The TDA2040 is not a common IC these days, but if you find one you can build this high quality...
We found this circuit in a 1992 Popular Electronics. The circuit has an optical sensor with LED...
This FM receiver tuning step circuit was found in a 1960 documentation. No information about the...