Home |
Search |
Today's Posts |
#10
|
|||
|
|||
Switching power supplies question.
On Oct 2, 11:37*am, wrote:
On Oct 2, 4:29*am, raypsi wrote: On Oct 1, 12:55*pm, terry wrote: We recently modified such a power supply to get a single 12 volt DC output at about 20 amps for a particular, amateur radio application. In order to do so we had to load one of the 5 volt outputs with a couple of amps in order to get the unit to work; but that's normal. Hey terry I did that very same thing loaded the 5volt with 5ohm at 5 watt. Ran my TenTec 526 off the 12 volt side of the PC power supply. I thought it was the sweetest thing since sliced bread. Then people started telling me I had this strange background noise. They asked me what was going on in my shack. I had this strange eerie noise in my shack, so they thought. Wasn't in my shack per say but it was the PC power supply. Nobody knew I was running a PC supply to power my rig. 73 OM n7zu I also use a modified PC power supply with no problems. I did add a filter removed from a commercial computer SMPS. I don't know the values of the components but its a Pi filter and the inductor is wound on what looks like a ferrite rod. The caps are some pretty big disk that had the writing rubbed off of them a long time ago. As Grumpy put it. I like to "Frankenstien" some of my projects. I have been giving some thought as to what it would take to modify a PC power supply for HV use. I have been thinking along two lines, 1 Connect a second step-up transformer before the rectifiers. 2 Replace the transformer with one with a HV winding putting a 5volt winding on the new transformer for loading and feedback. Jimmie- Hide quoted text - - Show quoted text - Great info: Thanks for all the ideas and especially about the warning that the HV would be on the line side (input) from115/230 volt mains. Unless a 60 hertz full isolation transformer were used; the weight and size of which sort of negates the idea of using a lighter weight SPS! I too used to fix TVs without power transformers, using selenium rectifiers (boy could they stink!) and voltage doubler circuits to provide B+. That was back in the mid late 1950s. I also made up a little B+ power supply in a box clipped in during house calls to show a customer that the problem was indeed inside the chassis and it had to be taken away for a 'bench job'! By that and means of never charging for a house call if I didn't fix the set in situ; built up a reputation for straightforward dealing which, despite the slightly funny accent of a British immigrant to Canada, some 15 years later, may have helped me become elected to the areas first town council? And that in a day and age when TV repairmen didn't have the best reputation in the world (well at least around here) for ethical dealings! These days customers are a lot more cynical and questioning; and rightly so! BTW first heard about SPS in the telephone industry, before PC were common; when power supplier representatives started telling us about 'rectifier/power supplies' that had efficiencies of over 80%. |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
QUESTION: Fun with Svetlanas or Staying alive with kV power supplies | Homebrew | |||
two 25 amp radioshack switching supplies | Equipment | |||
two 25 amp radioshack switching supplies | Equipment | |||
FS MFJ 25 amp switching power supply | Swap | |||
Newbie question about power supplies | CB |