Coil Flyback Current / Voltage

MisterBill2

Joined Jan 23, 2018
27,528
I suggest an experiment of leaving the diodes off and seeing how many operations it takes to cause any visible damage to some contacts. Just wire a relay with the coil in series with the normally closed contacts and then power it with the specified coil voltage. This will be a worst case situation because the coil current will be interrupted before the contacts fully open. It will be a classic buzzer circuit. It will also be rather educational.
 

MisterBill2

Joined Jan 23, 2018
27,528
Take a look at a door buzzer if you can find one, or one of the electromechanical bells that use the similar scheme. They last a very long time and they have no contact protection. In addition they do have a serious spark that will produce an ozone smell in a fairly short time. Of course, the bell and the buzzer do have enough moving mass to fully open the contacts so that the arc can extinguish completely before the next operation.
The contacts that do suffer a lot of damage are those made of solder blobs instead of the more durable materials.
 

Danko

Joined Nov 22, 2017
2,169
So in my set up/experiment I have the flyback diode, but also ( in series) with the negative side of this LED array to the Positive side of the diode, Positive side of LED Array to ground.
The Array of LED Strips are wired in parellel, I don't have any information on them, as I couldn't find them online, but im assuming the individual diodes in the strips are wired in series. I recovered them from a 120v LED Flood Light.
During the "open" I can get the entire LED array to light up very intensly. The LED's will flash rapidly, however as the frequency increases they will stay on without any noticeable flashing.
If the " flyback voltage " is limited to the 0.9 volts, how would it be possible to have this entire, LED array light up so intense. ?
Instead one diode with forward voltage 0.9 V you use complex diode with forward voltage 90 V (for example).
Your chain of diode in series with series/parallel branches of light emission diodes has properties
of alone diode with high (90 V) forward voltage.
Nothing magic.
 

Thread Starter

ben sorenson

Joined Feb 28, 2022
181
Instead one diode with forward voltage 0.9 V you use complex diode with forward voltage 90 V (for example).
Your chain of diode in series with series/parallel branches of light emission diodes has properties
of alone diode with high (90 V) forward voltage.
Nothing magic.
I didn't say it was magic, I'm still learning, so it was more of a questions, not a "look what I can do" statement.
 
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