I have a power supply that reads 12 volts on the output but when I connect two 12V fans the voltage drops to about 4.5V. What electronic component do I need to replace? Is it a bad capacitor or transistor? Let me know if you need more information.
Usually this kind of trouble arises due to weak capacitors. Check / replace capacitors.
A diagram of the circuit would give the most information and allow for the best solution. Baring that, a general discussion may help but only a little. 1) All power supplies and circuits have impedance or resistance that is internal. There are no perfect wires, transformers, etc. This means that when you check the open circuit voltage (the voltage when there is no load attached to the power supply) it will read the highest voltage available. Normally when you connect a load, the power supply delivers a current to that load. The current flowing in the circuit will cause a voltage drop along the wires, transformers, coils, capacitors, etc. that causes the voltage at the load to be less than the supply voltage. (I am ignoring the effects of capacitors on a three phase power line here). This may be a small amount of voltage drop or a large amount depending on the size of your power supply and the amount of load current that must be supplied to the load. 2) The power supply must have the necessary capacity to drive the load. For instance you would not be able to use a 10 watt power supply and connect 100 watts of load to it. Based on the above, is the power supply big enough to drive the fans? Did it supply them previously without a problem? If the answer is yes, then there is a problem with the supply that needs to be repaired. The type of supply will make suggesting a repair solution very hard without the diagram or schematic. Look for a partially open circuit or poor connection first. Then look for a failed component. This will depend on the component (fuse, capacitor, transistor, IC, etc.). Wish this could have been better but I just do not have enough information. Hope this helps, Newton1Law What make model refrigerator do you have?
