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.
We found this circuit in a 1997 documentation. Its purpose is to fan an inverter for fluorescent lamp...
We find this circuit in a 1994 technical documentation. The circuit has a 12 V input and a 33 V...
In the figure we show how two diodes can be used to simulate the center tap of a push-pull driver step....