Search results

  1. Kain

    Dual CMOS based timer problems...

    In this case there is not need of lower resistance actually. The thyristors that are on the schematic are sensitive gate ones and require very little current to triger. The funny thing is that it actually works even the way it's made right now.  The things go wrong when I wire up the timer in...
  2. Kain

    Dual CMOS based timer problems...

    Ok, what happens if the gate of those thyristors is floating? I will try shorting though to see if this fixes it. Thanks for the reply.
  3. Kain

    Dual CMOS based timer problems...

    Ok. There is the schematic with the bridge rectifier connected correctly. By the way, if this sort of power supply is not using bridge rectifier I wonder why do we have this published in here: http://www.electronics-lab.com/projects/power/022/index.html This is exactly what I used without much...
  4. Kain

    Dual CMOS based timer problems...

    Ok now. Do not pay this much attention to the PSU part. I know it's not correctly drawn, but I know how to build it correctly and it does it's job well -  I am getting stable 13V out of it. As about safety I know that it is not safe to have mains all over, but you didn't know that this device is...
  5. Kain

    Dual CMOS based timer problems...

    I tried to connect 1 and 15 to ground and as expected there was no change. It acts in the exactly same way. Any other ideas? I hope the PSU part pf the schematic is clear already  :)
  6. Kain

    Dual CMOS based timer problems...

    Ok now. I do not know if you saw the 680nF capacitor which you should note is connected before the bridge rectifier. As hopefully we all know capacitors have reactive resistance to AC, which means that we limit the current to way lower value, and this is why the zener is still not blown up  ;D...
  7. Kain

    Dual CMOS based timer problems...

    I have built a timer circuit based on CMOS 4538 which consists of 2 monovibrators. I am getting some sort of problems, such as bouncing and wrong timing. Do you see anything wrong with the schematic that i posted because I don't see it. Maybe i overlooked something... There is no noise in the...
  8. Kain

    Don’t over rev your Intel!

    Well, if you overclock the c**p out of your new PC it will run even faster
  9. Kain

    Convert 0-30V 3A PSU to 5A or more

    I just measured voltage between pin 6 and pin 4 for on U1 and it was 9.08V. When one calculates the gain on U2 it's arround 3.8 which is what it's supposed to be. I wonder why I don't get 11.2V on pin 6 of U1
  10. Kain

    Convert 0-30V 3A PSU to 5A or more

    Well, this is the schematic stright from the CAD. I believe it is the correct one that I should be using. Do you see anything wrong with this one?
  11. Kain

    Convert 0-30V 3A PSU to 5A or more

    Ok now, I already actually have 1k for R4 and
  12. Kain

    12V / 5A Transistor Switch

    Ok now, I tried the phase shift control and it works fine enough for my needs
  13. Kain

    12V / 5A Transistor Switch

    Hi Alun. I didn't say it is hard, I just decided tro make it hard by avoiding transformers  ;D. So you think that the Phase Power Regulation (light dimmer and so on) can do it stright from 110 VAC?
  14. Kain

    Step-up PSU with TL499A

    Actually the reason why I am making it is because I want to power my programmer stright from the USB port which can supply 5V @500mA max. My programmer requires 18V @ 50mA so I wanted to boost the USB's 5V to 18 or 20V and use a single cable to connect the programmer to any PC (no power adapters).
  15. Kain

    12V / 5A Transistor Switch

    Yes, initially I thought about transformer, but then I decided to make it more challenging. Oh well, I guess it's too much of a headache. Right now i was just thinking about Phase Power Regulation. Since the sine wave is cut of at certain point, can't I just cut it at 12V and then rectify the...
  16. Kain

    Step-up PSU with TL499A

    Well, to be honest it never even started working on first place. I changed the chip once too and guess what - no change at all. I do not think I have overheated the part either - the soldering was really quick  ::)
  17. Kain

    12V / 5A Transistor Switch

    Fantastic... So, besides calling 911 what can I do to make this thing actually work, or any other suggestion?
  18. Kain

    12V / 5A Transistor Switch

    Ok, here is a quick drawing of what I was thinking about. I was thinking about current limiting resistor in the collector, but I have the feeling I will be cooking my dinner on it...
  19. Kain

    12V / 5A Transistor Switch

    Oh, and by the way, I am trying to use this switch stright from 110VDC...
  20. Kain

    12V / 5A Transistor Switch

    Recently I had to use some 12V electrical clutches that draw about 4A continuosly under operation. I wondered if I can make a simple 1 transistor switch that can take this whole load? I was thinking of common collector configuration with zener stabilizator in the base. I do not care of any...
Top