Found in a 90s Radio Electronics, this circuit uses a ceramic capacitor (C1) as a sensor. The operational amplifier is a double 741 of the time.
This driver for audio signals using the TAA435 integrated circuit was found in Philips 1968...
This circuit was published in an article in Electronics Now magazine in October 1995. The circuit...
The configuration shown in the figure is one of the most traditional when it is desired to produce...