OpenSprinkler Forums Hardware Questions OpenSprinkler Pi (OSPi) MOV or diode for DC OSPi Reply To: MOV or diode for DC OSPi



MOV and TVS are designed to handle high surge voltage and are recoverable as soon as the high voltage is removed. Standards diodes like 1N4007 are not designed in the same way, and will be permanently damaged if the voltage exceeds their design maximum. Also, they don’t clamp the voltage so they are pretty much useless for protecting the circuit against high transient voltage.

Comparing MOV and TVS: MOV is cheaper but it will deteriorate over time (every time high voltage is present, it sacrifices a little bit of itself to dissipate the energy). TVS diode is more expensive but is more durable, and is available in surface mount packaging so is easier for surface mount soldering.

$5 valves should be good enough. I don’t know the particular model you are looking at, but valves are pretty cheap these days.