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so i have a pc power supply and i am going to use a pci cable to draw power from for a led lighting system and the led light system can only take up to 12 v at 2 a will that destroy the led light system or will it be fine? (also i cant open up the box that controls the light system to fix the blown fuse)
i have machine of fabric raising. the machine manufacturer has installed the dc mechanical brake on Ac main motor. the winding coil fit in dc mechanical brake. it was burned. after repairing it has burned again and again. despite same dc card and voltage. now, coil repairer says for reducing the dc voltage. now coming out dc voltage 230. but, we required 170 volt dc. reply.
There are 2 ways of doing it and both are heat producing, either way the excess energy is lost out.
1. add a small value resistor in parallel to your power source and it can be calculated as below. Plus an additional zener for over voltage protection.
say your source current rating is Ir and your resistor draws I1 and your sink or target is Is (eye sink).
Now Ir = I1 + Is, imply I1 = Ir - Is (i.e. Rating current - Sink/target current)
Since the parallel resistor maintains the potential needed by your device we calculate the resistance value = 12volts/ I1 (i.e. standard 12 volts divide by Current through resistor). It will be a high wattage wire coiled resistor in most likely case and would require cooling so that you dont fry anything unintentionally.
2. using an inductor to save up energy build and a fast switching RC circuit which discharges the inductor pretty quick before reaching the specified charge. Need to do the calculation as i have become rusty.
3. use a high capacity regulator chip like 78H12A. Need to check if it suffices for 12V and 5Amps output which it gives out.
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Posted:Sep 30, 2010
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