This circuit from the 80's makes use of two transconductance operationals of the time. Modern equivalents can be used. The circuit does not need to be powered by a symmetrical source.
This circuit should be used with low frequency signals only. The circuit is from a documentation from the...
This alarm circuit was found in the April 1975 issue of Radio Electronics magazine. It is a basic...
This circuit supplies 5 V from two AA batteries. The output current is 4 mA, resulting in an 11 mA...