This proximity relay circuit was found in the July 1990 Radio Electronics magazine. The supply voltage should be according to the relay used.
This circuit is from September 1984 Radio Electronics. The frequency can be changed by changing C1 and...
The voltage gain of this DC amplifier is 100 times, given by the relationship between R2 and R1....
This circuit appears in other articles in this section, but it is very interesting. It is a...