Over Voltage Protector Circuit

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Here is Simple Over Voltage Protector. This circuit protect your circuit from over voltage. A silicon-controlled rectifier is installed in parallel with the 12-V line and connected to a normally-closed 12-V relay, K1. The SCR’s gate circuit is used to sample the applied voltage. As long as the applied voltage stays below a given value, SCR1 remains off and K1′s contacts remain closed, thereby supplying power to the load. When the source voltage rises above 12 V, sufficient current is applied to the gate of SCR1 to trigger it into conduction. The trigger point of SCR1 is dependent on the setting of R1. Once SCR1 is triggered (activating the relay), K1′s contacts open, halting current flow to the load.

Lead Acid Battery Desulfator Schematic

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This is my first printed circuit board battery
desulfator. The unit is pretty small about 2.5″ x 2″ in size. I laid
out the circuit last week and the printed boards arrived today.

It took me a about two hours to assemble and test the first unit. Oddly
enough everything worked perfect. The pulsing sounds good (you can
hear it whistle), the components are not over heating, I am able to
pulse at 180mA while the other desulfators are only doing 60mA. At
this point I’m just going to confirm a few more short tests then start
selling these units. They will go for $50 each and I’ll post them up
for sale next week. You can write a comment to this post if you think
you want one. These units should do a good job of restoring neglected
lead acid and Ni-CD chemistries.

Originally uploaded by mikeysklar