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.
We found this configuration in a documentation for radio amateurs from 1974. The circuit can be...
Texas Instruments' low power operational amplifiers OPAx196 can be found on Mouser Electronics....
This low power amplifier circuit for speaker or phone is from the Philips Databook of 1990. The...