This sensor circuit for currents of the order of nanoamperes was found in an American documentation from the 1980s. The components are from that time.
In the figure we have the typical circuit of a stereo decoder using the TBA450N integrated...
This test for electrolytic capacitors was found in the October 1960 Radio Electronics magazine. Note...
The selected circuit is from the Texas Instruments optoelectronics manual. With it you can receive...