Zero Crossing Detector LM139 (CB14229E)

We found this circuit in the 1994 National Semiconductor Linear Applications Handbook. The circuit does not need a symmetrical source.

| Clique na imagem para ampliar |

Indicator Light 555 (CB13608E)
When the input of this circuit goes to high level, the LEDs start to flash alternately. The...
Sonic relay (CB23784E)
This circuit already uses an integrated circuit from the time. Note the different encapsulation of the...
Lead Acid Battery Charger (CB26301E)
This power charger was found in a 1990s issue of Popular Electronics. Integrated circuits must be...