We found this circuit in a Poptronics from 1998. The circuit can be extended to more competitors with another 4011. The power can be made with voltages from 6 to 12 V.
With this simple tester you can measure the gain of an NPN or PNP transistor. The instrument can...
I found this circuit in an old Argentine publication from 1973. The components are no longer...
Used with telephones at the time, this circuit was found in Popular Electronics from the 90s. The...