This peak detector has a memory to prolong the response. The circuit is from American documentation from the 1980s. The supply does not have to be symmetrical.
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...