Diode Tester (CB22137E)

This diode tester was found in an English publication from the 1980s. Transistors are general-purpose types of the time.

Wireless CW Monitor (CB4179E)
Placed near a telegraphic transmitter (CW) and with a small antenna or pickup, it reproduces the...
Word Filter (CB13200E)
The LM387 integrated circuit used in this project is not very easy to obtain. The circuit, from an...
15 mm Optocoupler (CB14666E)
The recommended distance between the emitter and the sensor of this coupler is 15 mm. The circuit is...