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  • Users: JJMI
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  1. JJMI

    Transformer for SMPS

    I have tried to make a transformer for my SMPS for a while, but all of these tend to saturate. I saw my distributor carries standard toroid transformers for the use with 115 or 230 VAC. I was wondering if I could use a 50VA backwards, of course with the proper winding ratio. If I could do...
  2. JJMI

    DC-DC converter issue

    Oh, I seem to have answered my own question. I have just tested the transformer with a wire of .0078 ohms, pulse shorting it by hand, causing an AC voltage to be produced on the secondary; the wire became extremely hot, while the transformer remained cool. I thank all whom have E-mailed me...
  3. JJMI

    DC-DC converter issue

    I am using a NJM2360D, switching at around 98kHz, with a 1.5a internal transistor to drive the MOSFETs. When it was working with a 5-watt 680 ohm resistor, the MOSFET was down at 80 F with only the 6x4 inch case as the heatsink. A 200 ohm resistor is between the gate and ground (a resistor is...
  4. JJMI

    DC-DC converter issue

    A few days ago, the MOSFET (an IRF1407) blew. I saw its temperature was up near 260 F. Oops. It was driving a home-made transformer (a toroid inductor with another wind for the secondary) that has a resistance of .005 ohms, while the IRF1407 has a RDS(on) of .0078. The question I have is...
  5. JJMI

    ALUMINIUM VS. COPPER CONDUCTORS FOR DC SUPPLY

    For wire, aluminum has a higher resistance than copper, which means that if aluminum is used over copper, then the wire will be of a lower AWG (thicker wire). Aluminum also tends to corrode if left bare for a good amount of time, or if it becomes wet. Soldering the wire to the connections...

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