This circuit was found on an old EDN and can be used as a shield. Optical couplers are from the era and modern equivalents can be used.
May 2017 - Mouser Electronics is delivering a voice recognition kit from NXP Semiconductors. The...
This circuit allows the use of an electret microphone with a 1.5 V source. We found it in the...
This small transmitter sends signals to the 7 MHz band, but can be modified to operate at other...