This circuit indicates the logical level of a CMOS circuit, extracting the power from the circuit being analyzed. The circuit is from an American magazine from the 90s.
Any general-purpose germanium or silicon PNP transistor can be used on this receiver. The handset...
When this circuit is activated the LED flashes for a moment indicating that the function has been...
In the circuit of the figure, when pressing S1 the sound varies according to the value of R2 and...