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 width of the pulses produced by the oscillator in the figure is determined by the value of R1,...
We found this approximately 1.5 kHz oscillator in Texas Instruments technical documentation. The...
This circuit was suggested by old French documentation, but it can be used as a shield, in which...