Found in a Popular Electronics from the 80's, this circuit makes use of a time integrated to control a relay in a timed way. R2 determines the activation time.
This circuit was found in a 90s Radio Electronics. It is intended to amplify the sound channel of...
A bridge with greater sensitivity and, therefore, lower consumption for the microcontroller...
Found in a 1964 magazine, this is a small headphone amplifier from 500 ohms to 10 k ohms (magnetic...