This circuit appears elsewhere in this section, obtained from other documentation. The circuit is for lead-acid batteries and the lamp can be replaced by high brightness LEDs.
This receiver was found in the Radio Electronics magazine of March 1953. It tunes to the medium wave...
This circuit was found in a 1990 publication. The sensors are electrodes placed in the water tank...
The figure shows how to convert a rectangular signal into a triangular signal using an integrator. The...