Melody generator (CB9207E)

Found in an Elektor from the 90s, this circuit is based on components that are still common today. Power is supplied with only two batteries.

| Clique na imagem para ampliar |

Brightness control for LEDs (CB9711E)
This automatic brightness control that uses an LDR as a sensor, was found in American...
Voltage Reference MC3403 (CB15262E)
The integrated circuit is not common nowadays since the configuration was obtained in Motorola's Linear...
Voltage Controlled Inverter Shield (CB13305E)
This circuit is from a publication of the 70s, but it can be easily assembled with the BC548. The...