This circuit was found in a Popular Electronics from the 90s. The counter circuit is not common today. The circuit can be programmed for hourly intervals, according to the values of R4 and C2.
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...