We have many versions of biofeedback with the 555 IC on this site. This is another one. We found it in October 1986 Radio Radio Electronics magazine. The power supply must be isolated.
This simple timer is from a 1998 publication. Other operational amplifiers can be used, and the...
August 2017 - Rectron's Schottky Barrier Diodes can now be obtained from Mouser Electronics. The...
This circuit limits the intensity of an audio signal from a control voltage. The circuit is from a...