Oil change computer (CB6373E)

This electrochemical circuit monitors the conductivity of the oil indicating when to change it. The circuit is from an 1967 American documentation.

| 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...