Silent Alarm (CB6444E)

This circuit simply triggers an LED when the sensor is activated. The circuit is from a Popular Electronics of the 90s.

| Clique na imagem para ampliar |

Digital thermometer with the TL505 and TL502 (CB16050E)
This 3-digit thermometer, suggested by Texas Instruments, uses 3 integrated plus the display, with...
Sound Generator (CB4535E)
I found this circuit in an English magazine from July 1982. The circuit is still viable because all...
Portable ultraviolet source (CB7188E)
This 1965 circuit consists of a small inverter for an ultraviolet lamp. The circuit is from a...