Mini Megaphone (CB8952E)

Found in Popular Electronics' 90s, this small megaphone is based on LM386. The circuit uses a high impedance microphone.

Circuit for Observing Hysteresis (CB13953E)
We found this circuit in an old oscilloscope publication. With it, it is possible to observe the B...
Modulation Indicator (CB3882E)
This interesting circuit found in an old documentation uses neon lamp to indicate the percentage of...
Programmable Gain Operational (CB18630E)
This circuit was obtained in an American documentation translated in the 80's. The circuit can be...