This circuit was found in the February 1993 issue of Radio Electronics magazine. Some components depend on the crystal frequency and can be changed.
We found this receiver circuit for modulated light in a 90s Popular Electronics. Equivalent audio...
This circuit uses a Norton operational amplifier to generate 1 kHz pulses with a 1 to 60...
This is the analog part of the previous circuit with the pressure sensor for the altimeter. The...