Remote listening amplifier (CB21957E)

Today we can call this circuit a baby monitor. It is a microphone amplifier found in a publication by Hugo Gernsback from 1960.

| Clique na imagem para ampliar |

Wien Bridge Oscillator MC1776 (CB4498E)
The integrated circuit used in this project is not common today, but it can be implemented with more...
Digital signal isolator (CB8021E)
Found in an American publication from 1969, this circuit can be adapted to be used as a shield....
Ammeter (CB9660E)
This current meter with many scales was found in a 80s American documentation. The operational amplifier...