This signal injector and tracer (follower) was found in an old American documentation. The transistors can be general use and power is made with one or two common cells.
The filter shown in the figure can have its cutoff frequency adjusted between 2 kHz and...
This circuit is from a 90s Popular Electronics. It appears elsewhere on this site. Q1 can be any...
This simple bridge circuit can be used for impedance or resistance measurement using a high...