This circuit with a dual power supply generates sinusoidal, triangular and rectangular signals. We found it in the magazine Electronics Now of January 1996. The frequency goes up to a few megahertz.
This circuit can use a pendulum sensor. We found this configuration in a 1994 publication. The...
This circuit is from a 1964 Electronic Design. The sensor is an LDR and the transistors are...
This circuit works both as a preamplifier and activates a relay when speaking in front of the...