This circuit was found in an American documentation two years 80. The MOSFET is of double port, difficult to obtain now and the circuit has a tuning frequency determined by RC.
Indicated by a Popular Electronics of the 90s originally to measure the light determining the exposure...
Other operational amplifiers series, such as the MC34072, MC34074, MC35071, MC35072, MC35074 d...
Found in American documentation, this circuit shows how to polarize a FET in bootstrap mode. The...