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  1. Rleo6965

    DC power supply

    You have to connect ground of all ic regulators. It's safer this way than let it float. I forgot to place a diode that connect to Vin and Vout. This is to protect the IC regulator. Connect diode in such a way that diode symbol pointing to Vin.
  2. Rleo6965

    DC power supply

    I modified my first circuit so you can use 1P4T non shorting high current rotary switch. Vin still tied together and does not use switch.
  3. Rleo6965

    DC power supply

    That's another problem. Even fixed regulators have no Vin but their Vout was connected to another Vout of other fixed regulator. This will also damages the ic regulator. It's just like placing input voltage to Vout pin.
  4. Rleo6965

    DC power supply

    @CocaCola Thanks for enlighten me.
  5. Rleo6965

    DC power supply

    I got it. It's a 2 gang 4 position rotary switch. I don't think you can buy high current contact. This was only use for low voltage signal selection. I think this is the one that that short first the adjacent contacts before breaking the connection and make another contact connection. This is no...
  6. Rleo6965

    DC power supply

    Big mistake. Your using 2 separate DPDT and both output tied together. In either switch position upper switch output ( +5V or 6V) will short lower switch output ( 9V or 12V ). Your fixed voltage regulator will be damage together with your load. Avoid using switch on Vin. Tie them together and...
  7. Rleo6965

    DC power supply

    Can you show me the diagram in your mind. I don't know about DP4T. First time encounter this electronic term.
  8. Rleo6965

    DC power supply

    It's your choice to select the first circuit using LM317 Variable voltage regulator. It's simpler. Less component. More accurate. Be sure to place filter capacitors near the IC regulator and important don't forget the heatsink. Use higher gauge wire to wire Vout to Terminal Screw and ground wire...
  9. Rleo6965

    DC power supply

    Much simpler if you buy variable resistor to have accurate dc output. Long time I have not visit here. I'm busy DIY rebuilding my junk Mitsubishi 1.3L 4G13 engine. Same engine use by Proton Wira car there in Malaysia. Already finished rebuilding. Just waiting for mounting in my car. I can now...
  10. Rleo6965

    DC power supply

    Here's another circuit for individual output
  11. Rleo6965

    DC power supply

    Hi Vick, Try this simple circuit. You can use only 1 pc IC voltage regulator. Place heatsink on LM317.
  12. Rleo6965

    SHORTS, voltage across resistor converts to current

    If your troubleshooting a power supply with separate board or load. Remove connector of power supply before testing DC output. SHORT could be in your separate Load / board and not in the power supply.
  13. Rleo6965

    SHORTS, voltage across resistor converts to current

    The 450mv of the fluke meter probe will be applied on the resistor or diode under test. A certain amount of current flow on resistor / diode and this will be computed / converted in resistance value on LCD display of Fluke 87..
  14. Rleo6965

    SHORTS, voltage across resistor converts to current

    How about desolder components one by one and test resistance if shorted then solder it back again on pcb. I'm sure within a day you will surely find that shorted component.
  15. Rleo6965

    slim type ballast

    heatsink
  16. Rleo6965

    SHORTS, voltage across resistor converts to current

    What happened here? So many negative numbers and blood.:D
  17. Rleo6965

    modified sinewave ups

    Why so many conversions? Your avoiding to use low frequency 50 hz bulky transfomer for 230AC output. In your design. You still need 50hz transformer to convert 230DC to 230AC.
  18. Rleo6965

    PWM

    In my understanding. Pulse With Modulation or PWM in power supply circuit. Inverter frequency must be 20khz or higher and high pulse width was variable to control the dc output of rectifier diode.
  19. Rleo6965

    Help with understanding Polarity Selector switch

    If your Appliance have no AC motor. I think it would not be a problem.
  20. Rleo6965

    Help with understanding Polarity Selector switch

    You need AC Step UpTransformer that will conver 110V AC into 220V AC for your aplliance. Be sure to buy correct Wattage.
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