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.
This circuit was found in the June 1991 issue of Radio Electronics magazine. The circuit uses two...
The MOSFETs are of the type of power and the resistors have their values between 1 k and 10 k for...
In the figure we have the way to use an LED to increase the voltage of a zener. The increase...