We found this code key or coded keyboard in a publication from the 90s. The circuit uses components that are still common today and is powered by a 12 V voltage according to the relay used.
This variable voltage reference uses a Norton operational amplifier. The voltage is adjusted at...
This 6 transistor TR26 commercial radio was sold in Japan in the 60s. It is a super heterodyne circuit...
n be assembled with BC558 transistors for low power transistors and a BD136 for the output. The...