Found in the June 1987 issue of Radio Electronics magazine, this circuit uses well-known CMOS components. The circuit has a CMOS amplifier stage that drives a small speaker.
STMicroelectronics MP23AB02B MEMS Audio Sensor is a compact, low-power microphone built with a...
This circuit can be controlled by an LDR causing an LED to flash at a frequency given by C2. The...
We found this circuit in the Philips Databook of 1990. The circuit is indicated for low-cost...