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This circuit was found in a 80’s Popular Electronics. It issues a warning signal with the signal of the old type printer with parallel port.
This circuit can be implemented with other operational amplifiers. The formulas for calculating the...
This circuit is from a 1953 publication, consisting of an AM radio with 3 germanium transistors that,...
The sensor of this circuit is a common silicon diode and it directly drives a small cooler with a...