Found in an ancient American documentation, this circuit can generate signals up to 40 MHz for a Z80, microcontroller widely used at the time. The circuit must be powered with 5 V and also serves as a shield.
This two-color LED indicator was found in a Popular Electronics from the 90's. The transistor...
In this circuit the gain decreases as the input signal intensity increases. The circuit is from a...
This circuit was found in a Popular Electronics of the 90s. The output amplitude will be between...