This circuit was found in Linear Technology documentation from the 90's. The circuit uses components from that time, and can be powered by 5 V. In these conditions, it can function as a shield.
This Philips commercial circuit is from the 90's documentation. The integrated circuit must be...
We found this circuit in the September 1971 issue of Radio Electronics magazine. The sensor is an...
This circuit is from a Hands-On Electronics from 1987, but it can still be easily assembled, as...