This shield was found in a 90’s Popular Electronics. The circuit can be implemented with modern equivalent circuits.
In this circuit the output current is limited by R3. For a 300 mA current, R3 must have 12 Ω. For...
Found in Radio Electronics from the 90s, this circuit produces pulses to test an infrared...
This circuit was obtained from an American publication of the 80's. The integrated circuit is of the...