This circuit was obtained in an Electronics World of 1968. The operational amplifiers ones are types of the time, no longer used today. The circuit responds from less than 20 Hz.
We found this circuit in a 1997 documentation. Its purpose is to fan an inverter for fluorescent lamp...
We find this circuit in a 1994 technical documentation. The circuit has a 12 V input and a 33 V...
In the figure we show how two diodes can be used to simulate the center tap of a push-pull driver step....