Hello "Greenr" - welcome to the Forum! [Linked Image]

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Hi, does anyone knows what is the consequence of accidently reversing the polarity of the diode (i.e. the cathode connecting to the negative side of the relay)?

This will result in the Diode being connected in the "Normal" Forward-Biased direction.
Unless there is a Resistor, or some other means of limiting the Current (AKA: "Ballasting"), the Diode will draw high Current - acting as a Short Circuit.

Results will be:
<OL TYPE=A>

[*] Relay's Coil unlikely to latch closed - due to the extreme voltage drop,


[*] Diode will lose smoke, and after all smoke is lossed, it will become an Open Circuit - or,


[*] High Current level will either/or:
- melt fuse / open thermal cutout,
- damage DC power supply.


[*] Or all of the above - depends on how sturdy the Diode is.
</OL>

The reason to Reverse-Bias the Diode, is so clamping may be achieved during the time when the "Saturated" Coil reacts inductively to the rapid change in current flow.
The "Inductive Kick" flows in the opposite direction - and such, a Reverse-Biased Diode may work effectively in an active circuit, as a clamp during the inductive kick, and still block current while the Coil is in normal "On" operation.

Make any sense? [Linked Image]

Let me know if Yes / No

Scott35

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!