Continuity tester (CB7387E)

This circuit is from a Popular Electronics from the 90's. The circuit activates a buzzer with oscillator (Sonalert) through a relay.

1 uA Precision Source (CB5140E)
This current source was obtained from an 80's operating manual. The circuit can be applied to modern...
Family of Live Updateable Controllers for Digital Power Expanded
The dsPIC33EP128GS808 Digital Signal Controller Family now Offers up to 128 KB of Flash while...
ooooooo/ 1 kHz Sine Oscillator (CB4614E)
The circuit shown in the figure consists of a phase shift oscillator and its components have been...