ELF Monitor (CB21055E)

This circuit monitors extra-low frequency (ELF) fields. We found it in an American documentation from the 90s.

| Clique na imagem para ampliar |

Electronic Bell for Telephone (CB17982E)
The integrated circuit used in this 2002 project is not very common. It is powered directly by the...
Adjustable Voltage Reference (CB14049E)
We found this circuit in a 1972 RCA technical documentation. The comparator can be any type and C1...
Astable Neon (CB10504E)
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...