We found this good amplifier in a Japanese publication of 1966. Transformers are uncommon nowadays and the power supply is included. Power is a few watts.
This 100-second timer was found in a 2000 Poptronics. The magazine no longer exists, but the...
The 3-digit AD converter on this circuit is not very common today. It uses 2 integrated circuits to...
We found this circuit in the National Semiconductor FET manual. The components are calculated...