This circuit indicates when a rain is acidic by monitoring its pH. The circuit is from a 90s RE Experimenter Handbook. Some components used can be difficult to obtain today.
The circuit in the figure is suggested by Murata for an uPD75380 microprocessor and is based on a...
This circuit was obtained in a Radio Shack documentation from 1977. The sensor must have a...
The buffered phase shift oscillator circuit shown in the figure oscillates at a frequency of 2.9...