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Posts posted by steveggz

  1. I bought and assembled the parts yesterday. I used a "mfr. part# LD1085V12" for the voltage regulator. It has low dropout and is rated for 3A 12V.
    I used the recomended capacitors and a switch before the regulator.
    It works great. I have 11 nimh batteries in series that are rated 2500ma. They now output a constant 12V. My Magnavox Camcorder requires 12v 2A so im in good shape.
    The camcorder runs a lot longer than it did with the older lead acid battery.
    I also bought a nice battery charger to charge the rechargeable batteries.

    When I ordered these parts online I also bought a "mfr. part# LD1085V". Its also a low drop out, 2.85v to 30V 3A adjustable. I would like to make another battery pack for another older camcorder I have.
    I would like to use the "LD1085V" to make the required voltage for that camcorder. It uses two resistors in the diagram to get the fixed voltage.
    I posted a picture of the diagram. Can someone please tell me what "Vref" means?


  2. Hi. I would like to know to be on the safe side, is there any problem with having a fixed voltage regulator after a battery?
    I connected 11 AA NiMH 2500mAh batteries in series to get a higher voltage but I would like a different fixed voltage. If I connect a voltage regulator (connected with the recommended capacitors) after the battery would there be a problem?

  3. Hi MP, id like to thank you and Audioguru for your help. I found the problem, it was me. I feel like an idiot. I never learned how to read a multimeter. I am getting over 1A of current from my voltage regulator, I was reading it wrong. First I was measuring the current wrong but Audioguru showed me how, and then I read the numbers wrong. The decimal point fooled me, I was measuring at 10A on the multimeter.
    The video camera pulls around 680ma to 890ma without recording and with the light around 1.2A.

    Thank you very much for your help. ;D
    I love this forum :-*

  4. Ok, finally things are starting to make sense. I measured the current with the light turned on and it went up to about 125ma from 87ma. So what I did was, before I made the voltage regulator I was using a plug pack labled 9vdc 1A. It would work but when I tried some features on the camera it would shut down with a low battery sign. So I connected the multimeter to check current with that power supply and it is also very low, actually its the same as with the voltage regulator. I guess the camera doesn't use a lot of current.

    The weird thing is when I measure voltage with the 9v 1A plug pack it reads at about 12.2V.
    Almost all my plug packs that I have measure a higher voltage than labled. Do you think that the camcorders lable 9.6v really needs more voltage?
    At 9.6 volts it does not turn on, at 10v it turns on but turns off when I put the light on. At 12.2V with the 9v labled plug pack it stays on a a lot longer.
    Do you think the real required voltage is something around 12.5 or a little more?

  5. Hi audioguru, could the camera use up more that its rated 850ma on the lable?
    Il check the current with the light on but there is one problem, every time I turn the light on the camera shuts down. Do you recomend increasing the voltage to keep the camera on to take the measurment?

  6. No, it just sais 10v 850ma. I tried powering the camera again at 10v with the camcorders light turned on and it showed a "low battery" sign and turned off.
    It does the same thing with the 9.6v input connection on the back. For some weird reason im not getting enough current when it comes out of the circuit.

    Do you think it could be the size of the wire that runs through the circuit? What I mean is the wire on the capacitors and resistor are pretty thin, maybe they are causing resistance? For the resistor I got a 1/2 watt but the capacitors did not specify that so I got what it said on the web site. There wires look pretty thin compared to the incoming wires from the 12v 1.5a power supply.
    I dont know much about electricity but could that be the problem?
    I wish I was able to take a picture and show you how the components look on the circuit, il try to get my friends digital camera.

  7. I connected everything like you mentioned and I think I got an accurate measurement.
    I was unable to connect it through the little hole on the back of the camera(I dont know what those connections are called) which is 9.6v, so I used the connections for the battery. The input voltage for the battery is labled 10V and 850ma. So I set the voltage to 10V on the voltage regulator and connected it properly this time. The camera, because I had it on "On" turned on by it self when I connected the multimeter probe to the positive. As it started up the current changed a little.
    First the current was under 100ma and when it was ready it was about 105ma.
    Does that seem right? Its labled 850ma, do you think camera manufacturers have higher current ratings for a buffer.
    I would like to see if the voltage regulator can actually go as high as 1A. I guess the only way to find out is to use a device that draws around 1A.

  8. Hi Audioguru, thank you for your help. Im really not familiar with this stuff. Before reading your second post I tried again and it came up around 235ma again but it looks like I am doing it wrong, no wonder it sparked every time I touched the leads to the ciruit. Im going to try again the way you explained it.

  9. Actually Im using it for a video camera. On the back of the camcorder it mentions the voltage (9.6) but not the current or ampege.
    I measured the current on my mutimeter without a load, meaning I didn't connect it to the camcorder and then check the current. Im new to electronics, is that the wrong way to check the current?
    Its good to know the resistor is right, im going to check the current again, this time with a load.

  10. Hi. Today I bought and assembled parts to make a voltage regulator in reference to couple of web pages but mostly from http://casemods.pointofnoreturn.org/vregtut/tutorial-full.html.
    I attached a picture of the schematic.
    Alun also showed me a schematic very similar to this one. Im sure that this schematic works because of the many tutorials on the web.
    After assembly I measered voltages and they are working great. I can get to the 9.6vdc I was looking for. But there is a big problem, the amprege or current is very very low. Its at a constant 235mA.
    The input voltage is 12vdc and 1.5A. I measured this before and after, and the power is accurate. But my ouput Amprege after the circuits is 235mA.
    Can anyone figure why? By looking at the schematic, is there anything wrong? I checked my circuits many times and it looks accurate with the schematic.
    Could it be the resistor? Or the pot?


  11. Hi. If I lost a plug pack for a video camera but had another plugpack with the same voltage but different amprege (higher amprege), would it damage the components or does the camera use only what it needs?
    I know with AC a motor if pluged in a 15amp socket will only use what it needs, like 4 or 5 amps, but is it different with DC electronic components?

  12. Thanks for the replies, I went to radio shack today but had no luck finding the parts I needed. The employee had no idea what I was asking for. I found a site called mouser electronics, il try to see if I can find it there.
    Thanks Ante, 9.6 is exactly what I need. I have couple silicon diodes so il use one like you described.

    I have another question, il post it as another topic for easy searching.

  13. Hi Staigen, thanks for the reply. Sounds good, I didnt come across voltage regulators when searching. Just for the sake of knowing, would connecting silicon diodes reduce the voltage by 0.6v?
    And is it true that resistors dont reduce the output voltage anly the amprege?

  14. Hi all, I have a 12v 1 amp dc transformer that I would like to make 9.6v. I have never searched the internet more than I have to come up with nothing. Please help. I dont know much but im a quick learner.
    I thought adding resistors to the transformer(after the transformer) would reduce voltage but it seems that resistors bring down the amprege. Then I read about diodes.
    If I add silicon diodes to the line after the transformer will it reduce the voltage by 0.6 for each diode I add? If so, what kind of silicon diodes do I need and do they sell them at radio shack?
    I also heard of zener diodes, seems more complicated.
    The reason I would like to reduce the voltage is to use it for an old video camera that uses 9.6v.
    I dont want to buy a special transformer, Id really like to modify this one.

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