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 amplifier was found in an English publication from the 60's. The transistors are germanium of the...
We found this configuration in a 1974 technical documentation. It can test both TTL logic circuits and...
This circuit for 12 V x 2.2 W lamps was found in a documentation from the 70's. The circuit uses...