The frequency of this circuit depends on C1 and, for the indicated values, it is 1 kHz. Equivalent operational amplifiers can be used, and the power supply must be symmetrical.
The filter shown in the figure can have its cutoff frequency adjusted between 2 kHz and...
This circuit, which uses a quadruple comparator, was found in old American documentation. The...
This shield for controlling the direction of rotation of DC motors up to 500 mA with BD135 / 6 and...