This high-Q low-pass filter was found in the October 1990 issue of Radio Electronics magazine. The frequency depends on the capacitors used and is on the order of a few tens of hertz.
We found this circuit in a 1995 documentation. It is a two-channel preamplifier for supplying a...
In the figure we have the way to connect solar cells in series in order to increase their voltage. The...
This circuit is from the 1990 Motorola Data Databook. The circuit can be implemented with...