This circuit is from a 1978 Texas Instruments optoelectronics manual. The trimpot adjusts the LED current. Other currents can be adjusted if they are within the capacity of the FET.
Here we show an oscillator that uses an LC network. The upper limit depends on the power-supply...
This circuit from a Popular Electronics from the 90s allows you to use an old PC as a digital...
of the National Semiconductor of 1994. The same technique can be used with other operators and the...