Fuse relay for battery charger (CB7137E)

This protection circuit for battery chargers was found in an old Elektor. The relay is according to the voltage of the charger.

AM Modulator (CB4917E)
We found this circuit in a Linear Technology component manual. The circuit also has a DC zeroing...
LM3914 20-LED Voltmeter (CB25457E)
This circuit has a scale of 0 to 2.56 V, but it can be changed by changing the values of the...
Divide-by-6 TTL por 6 (7490) (CB227)
Figure Bellow shows how to use a 7490 (TTL) IC to divide the frequency of a TTL signal by 6; The...