Search results

  1. Hero999

    Design new 0 to 30V power supply.

    Done. A 39V zener such as the BZX85C39 or 1N4754A. I've simulated this with three zeners in series giving 40V which is near enough. I might as well upgrade the voltage to 33V as the simulation clearly shows it's possible. It does do Bode plots but it's not something I've used before so I'll...
  2. Hero999

    A cool project - Replicate Steorn's Orbo - A back EMF-less free energy motor!

    It doesn't seem to be anything new. It's just a DC brushless motor except it uses toroidal coils. I doubt it breaks Lenz's law. One explanation is the change in current and voltage is very small because it's very inefficient i.e. very little power is being converted to mechanical energy, most...
  3. Hero999

    Design new 0 to 30V power supply.

    You can build it now if you like but don't expect it to be any good. I'm expecting there to be problems with the first build. I remember designing something at work. I wanted to build a prototype but the boss wouldn't let me. It didn't work properly but I did tell him. He couldn't blame me...
  4. Hero999

    Voltage Controlled Switch

    You beat me to it Alex. I'd recommend the LM311 because it can directly control a small relay.
  5. Hero999

    Design new 0 to 30V power supply.

    Yes, I noticed your post but had the self control to go to bed. ;D I don't see how that will help. As you said the turn-on voltage wll be higher which I think counteracts any benefit of having a lower capacitance, suppose the turn on voltage is doubled and the capacitance halved, we still have...
  6. Hero999

    Design new 0 to 30V power supply.

    You're right, I thought it was TO-220 but the datasheet clearly states SMT.
  7. Hero999

    Design new 0 to 30V power supply.

    Each to their own I suppose. I thing 1.5A is good enough for most applications, for high powered stuff a regulated power supply becomes less important so I make my own unregulated supply using a Variac, a mains transformer, a rectifier and a filter capacitor. Now as this supply isn't going to...
  8. Hero999

    Design new 0 to 30V power supply.

    More and more MOSFETs can be added. The limitation is that the increased gate capacitance will slow things down. As drawn, the total gate capacitance is 3.74nF with R4 = 10k the time constant is 37.40_to_30V_3A.asc.txt
  9. Hero999

    Design new 0 to 30V power supply.

    30V@3A was the original design spec. Increasing the current capacity won't be a problem but the a voltage would be. The op-amp needs to be powered from the output voltage plus 6V to turn the output MOSFET on. The trouble is most op-amps are rated for 44V or less. I'm sure it's possible to...
  10. Hero999

    help po, 5v 3amps supply

    Here's an AC adaptor that will do that. http://www.microwarehouse.co.uk/catalogue/item/DLIN022 This is an English site. I think you meant to post at the Filipino site which looks similar to this one, don't worry you're still welcome.
  11. Hero999

    Design new 0 to 30V power supply.

    Both the upside down and universial op-amp symbols point to UniversalOpamps.sub which should already by in the sub directory, it's a standard LTSpice library which should already be there. I got the file name wrong earlier, it's Upside dwn Universal opamp .asy I missed the space which was...
  12. Hero999

    Design new 0 to 30V power supply.

    Here's the .asc file and .asy file, just remove the .txt extension. I realised that adding a potential divider or switch to the summing junction of an op-amp is probably a bad idea unless it's directly mounted on the PCB or connected with screened cable. I haven't simulated any transients yet...
  13. Hero999

    Design new 0 to 30V power supply.

    I haven't decided yet. At the moment I've used the generic op-amp model found on LTSpice. Guess. Hint: it isn't an input, it's an output. As drawn the RC time constant is 10
  14. Hero999

    Design new 0 to 30V power supply.

    Alex, The trouble with using a stabilised supply is it won't test the ripple rejection. PicMaster, That looks like it aught to do the job. Attached is revision 1, it's not finished. As you can see, the power supply for the op-amps is taken from a voltage doubler. This is required because the...
  15. Hero999

    Design new 0 to 30V power supply.

    I agree, it needs testing, as well as a peer review. There are other components such as a large 24V transformer or a 3A 35VDC power supply. I could test it at lower currents and voltages using my 1.5A 30VDC PSU but it't probably isn't worth it. My intention is to build it, post the schematic...
  16. Hero999

    2 ch rf remote

    I doubt you'll be able to find the schematic, have you taken it apart and looked at the components? Of course it's possible that won't be any help because non-standard components are ofted used i.e. a chip on board which just looks like an epoxy blob. Toys often use microcontrollers because...
  17. Hero999

    Design new 0 to 30V power supply.

    I meant 50mOhm  ;D I like the timer on the current limiter. It's probably easier to implement it as a simple RC time constant in the feedback rather than a timer. A low offset amplifier sounds like a good idea but I would rather have something pretty standard, rather than a proprietary IC only...
  18. Hero999

    home remote control from hell

    The output is simply the contacts of a relay: NO means normally open. NC means normally closed. COM means common. See attached for a picture of what the switch looks like in the inactivated state. This is standard electrical engineering nomenclature, you'll see NO, NC and COM on many products...
  19. Hero999

    Design new 0 to 30V power supply.

    As you all probably know, the 30V power supply project on this site has many errors and design flaws. I'm thinking about designing a new one from scratch but before I do, I'd like to know whether anyone will test it for me? It's not something I want to build myself because I don't need it. I...
  20. Hero999

    The flashing Heart(i have some doughts)

    It seems silly to run the thing off 12V and connect all those LEDs in parallel. LEDs shouldn't be connected in parrallel anyway because they all have slightly different forward voltages. The LEDs should be connected as several series strings in parallel to save power.
Top