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  1. sureshot

    Resistor values.

    Well it was my stupid mistake /-: that one wire I put into the regulators input, can't believe I made such a simple mistake. Wired up now the 2 x transistor version is at 12.07 volts no load, at 50 watts its 11.80 volts steady, at the maximum (Which I would go no higher) 100 watts its steady at...
  2. sureshot

    Resistor values.

    Thanks Steve. I still have to reconfigure it, but I'm optermistic. There are a couple of by pass 0.1 ceramic disks directly on the 78xx leads, can't see it in the picture of the 2 x version, there are two the same again but on the board of the 1 x version, but a liitle further from the 78xx than...
  3. sureshot

    Resistor values.

    Fresh eyes and all that the following day... I've found a wire that I soldered in to the regulators input, this lead would have shorted the base resistor leaving it redundant, and the pass transistors not conducting. "Ever felt stupid" I do at the moment. Can't be 100% sure until I alter this...
  4. sureshot

    Resistor values.

    Here is the single transistor version as per the single version schematic above, and the 2 x transistor version as per the 6 x schematic above.
  5. sureshot

    Resistor values.

    I have been over the 2 x version of the 6 x schematic carefully a few times to make sure I've missed placed nothing. Where you say don't worry about layout, if you look at the single transistor version, and the 6 x version the resistor placements are different. The base resistor is not in series...
  6. sureshot

    Resistor values.

    First thank you for the replys and help. My first build was exactly as the schematic above with the single pass transistor in it, not a single transistor version of the 6 x transistor schematic. The two schematics (colour one's) differ in the resistors placement. As seen, the single transistor...
  7. sureshot

    Resistor values.

    Yes I did Davenn. It works well, the resistors to the emitters in the six transistor version look different from that of the single version circuit. This is what I see.. In the single transistor version the input goes to the emitter before entering the (in my circuit, 7 watt 1R ceramic resistor)...
  8. sureshot

    Resistor values.

    The single transistor version in the picture above works fine, if anyone can throw any light on why a two transistor version of the 6 transistor schematic in the picture above fails to carry the current, using the same resistors as in the schematic. So a base resistor of 100R 0.5 watt, and two 5...
  9. sureshot

    Resistor values.

    Yes, I used a 15 volt AC secondary. But a two transistor version with the same value resistors as the six transistor version didn't work. Well not stickly true ! Its output was the expected 12 volts, but the regulator tried to do all the work. The transistors where not forwardly conducting as...
  10. sureshot

    Resistor values.

    Many thanks Steve and Davenn appreciate the help. I know protection needs adding on the input circuit and the output. If the model works well in a test over time loaded, then I will add the extra protection on both input and output, and built it in a tidy chassis case. Thanks again fellas.
  11. sureshot

    Resistor values.

    So i can see R7 limits current into the voltage regulator, so its position must be correct, what i am really looking for is do i have the values correct for a two transistor version, of 16 ohms for a base resistor, and 10 watt ceramic ballast resistors of 0.5 ohms each two of these one for each...
  12. sureshot

    LM317 question.

    No it won't let me upload the schematic, but its in my post in circuit help section of the forum.
  13. sureshot

    LM317 question.

    Most of what I'm powering is radio equipment. The reason for playing about with the higher current, although I have run into noise from the supply's when using smps typically atx and server units I've converted. So I'm trying to go with linear and series pass transistor circuits. I have built a...
  14. sureshot

    Resistor values.

    The only thing I can see what I think is wrong, is R7 should be going to the base of the transistors, and not in series with the input like it shows in the schematic above.
  15. sureshot

    Resistor values.

    Once I've tested this second version of two transistors, and voltage regulator I will find a suitable crow bar circuit or over voltage, over current needs only yto be a fast blow fuse. 10 Amps to drive an amplifier. I was looking to see if my values of 16.6 ohms base resistor, and two 10 watt...
  16. sureshot

    Resistor values.

    This is the circuit I wanted to make a two transistor version of, sorry about image quality, I'll try and post a better image.
  17. sureshot

    Resistor values.

    I can't seem to upload an image of the schematics so posted a link. The 30 Amp PSU is the circuit, and I've built a single resistor version, but wanted to know if I have the resistor values correct for a two transistor version. http://www.zen22142.zen.co.uk/Circuits/Power/1230psu.htm
  18. sureshot

    Resistor values.

    After trying a 12 volts power supply circuit with a single TIP2955 transistor as a pass element, and a 78S12CV voltage regulator this works really well. This is the schematic with the single transistor. I would like the try and build a 10 Amp version with two of the same transistors. I think...
  19. sureshot

    LM317 question.

    Happy new year. Sorry I've been absent, thank you Hevans 1944. I have converted some atx power supply's, but none are variable at the moment. But they are good for high current uses, allowing some ripple above a linear on the output, and pwm fan control electrical noise, but handy high current...
  20. sureshot

    LM317 question.

    Yes there's no real short cuts for a proper circuit, it will pay long term to get it right with a decent build. But just to see what kind of poor regulation and for the sake of a handful of components I've got to build it and see, as odd as that might sound lol. Thanks for your help Hevans 1944 (-;
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