This circuit converts 12 V to 127Vac to power small electronics in the car. It was found in the 1993 edition of the Electronics Experimenter Handbook.
This circuit appears elsewhere on this site, but from different sources. Using the LM3900, we find this...
This interesting source or isolation transformer also allows to vary the output voltage by...
In this circuit the CA3140, an operational amplifier, is used as a comparator with the zener diode...