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  • ATX to Lab Bench Power Supply Conversion

    Hello Kokoro San. Be aware that many ATX power supplies have 12v split into 2 or more sub-supplies. Look at the sticker on the side of the ATX power supply for details. I would suggest using a battery charger to manage the charge process.I am not sure what you're asking about for diagrams?

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  • ATX to Lab Bench Power Supply Conversion

    Hello, good question!Using Voltage = Current * Resistance, we know that 12 volts across a 25 ohm resistor results in 12/25=0.48 amps of current flowing through the resistor. The other important formula to use is Power = Voltage * Current, so 12 volts * 0.48 amps = 5.76 watts of power, that becomes heat in the resistor. Since the resistor is rated for 10 watts, you're not going to melt the resistor but it may get warm over time.I wouldn't expect it to get too hot to touch, so perhaps the resistor has less resistance, and is therefore drawing more current? If I remember correctly, the wirewound resistors that can handle many watts usually have a large variance in the amount of resistance it actually has, compared to the "official" resistance. If you have a multimeter you can mea...see more »Hello, good question!Using Voltage = Current * Resistance, we know that 12 volts across a 25 ohm resistor results in 12/25=0.48 amps of current flowing through the resistor. The other important formula to use is Power = Voltage * Current, so 12 volts * 0.48 amps = 5.76 watts of power, that becomes heat in the resistor. Since the resistor is rated for 10 watts, you're not going to melt the resistor but it may get warm over time.I wouldn't expect it to get too hot to touch, so perhaps the resistor has less resistance, and is therefore drawing more current? If I remember correctly, the wirewound resistors that can handle many watts usually have a large variance in the amount of resistance it actually has, compared to the "official" resistance. If you have a multimeter you can measure the resistance of the resistor by itself, or you can put the meter in current measuring mode, and insert it in series with the resistor and measure the actual current. Let me know if you need more info about how to use a multimeter for this kind of investigation.If you could find a 100 ohm power resistor, that might work better. It would result in 0.12 amps of current instead of 0.48 amps. I really don't know how much current is needed for the minimum load, but I would guess that 0.1 amps would be enough. This would reduce the power burned as heat in the resistor down to 1.44 watts, so you could use a 5 watt power resistor instead of 10 watt.

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  • ATX to Lab Bench Power Supply Conversion

    Hello, good question! If you want to limit a specific binding post to only output a certain amount of current (1A, 2A, 5A, etc) then you need to use a fuse that will blow when the current limit is exceeded. Be aware that fuses are not very precise in terms of current limits, and there is usually a range where the fuse may or may not blow.Hope that helps, let me know if you have further questions, or if I didn't understand what you were asking.-Matthew

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