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.
This circuit tests quartz crystals of frequencies between 100 kHz and 10 MHz. The circuit is from...
We found this circuit at a January 1991 Modern Electronics. The magazine no longer exists, but the...
The ZN416E integrated circuit is uncommon today. It consists of a complete radio, like the one...