This circuit with a bargraph scale was found in a 90s Popular Electronics. The circuit measures the intensity of a sound in three scales. R14 works as a sensitivity adjustment.
This amplifier uses common transistors in a phase inverter configuration. Transistors must be...
This circuit generates a linear ramp whose frequency depends on the capacitor and the setting. The...
We found this circuit in a Popular Electronics from the 90s. Transistors can be modern...