This circuit is from a 1968 Texas Instruments documentation. The components are from the time and the sensor photodiode is difficult to obtain today. The circuit has a response from 10 Hz to 20 kHz.
We found this filter in the 1990 Motorola Linear Databook, but it can be implemented with other...
Instead of the lamps, LEDs can be used in series with 470 ohm resistors. The circuit is from an...
This low current solenoid driver was found in an ancient American documentation. The solenoid must be...