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  1. J

    reducing 5V to 4v or 4.2v MAX

    I don't think it will be possible to set the voltage on the converter I have as it is enclosed. Below is a pic of the converter I have. I think I will wire 2 1N5822 diodes in series and see how that goes. If the max voltage drop for each diode is around 0.525v then 2 in series will have a max...
  2. J

    reducing 5V to 4v or 4.2v MAX

    I have lots of 1N5822 Schottky Diodes in my toolbox, so might try using one. Plus I plan to put a diode on the 5V output feed anyway. Does anyone know what the typical voltage drop will be for the 1N5822 on lets say very low current draw to something like a 2A current draw? If on high current...
  3. J

    reducing 5V to 4v or 4.2v MAX

    Thanks for that very informative post. I'm basically running a Android tablet directly from a car power source and getting rid of the battery of the tablet. Currently it works fine with the 5V but I don't want to risk frying it. Most people have said that the tablet can support upto 5.25V and...
  4. J

    reducing 5V to 4v or 4.2v MAX

    I have a 12v to 5V 3A convertor. What would be the best way to further reduce it by at least 0.75V? I was thinking of a resistor but that will be generating a lot of heat. Is there a better way to reduce the voltage and have it stable? The current draw will vary. In most cases it probably won't...
  5. J

    12v relay with time delay and reverse polarity

    LOL ok, let me try and explain in another way I currently have a 12V relay. This relay is turn on and off by the connection from the 12V washer pump. When the relay is turned on, I want it to remain turned on for 3 or 4 seconds even if the supply that powers the relay is turned off. I also...
  6. J

    12v relay with time delay and reverse polarity

    Looking for some help in wiring up a 12v relay for my car. Basically, I have a 12V relay that is activated with my windscreen washer circuit. So when the washer pump is active, the relay activates. Problem is that the relay only stays active for the period of time that I hold the washer stalk...
  7. J

    Li-Polymer with i2c chip

    Because I am installing the device as a car multimedia display and in very hot sunny weather the temperature of the battery gets very hot without use and the tablet goes into thermal shutdown. Not to mention the risk of battery explosion. Quite a few people have therefore completely removed...
  8. J

    Li-Polymer with i2c chip

    I have a Google Nexus tablet which has a 3.8V Li-Polymer. I want to remove the battery completely and run the tablet directly on a step down converter running at 3.8V. I've tested the theory and the tablet works fine. Only problem is that the Li-Polymer battery of the tablet has 2 additional...
  9. J

    USB 5V power from 12V car supply

    Do they sell fast blow fuses in blade format? I think they just in the glass style. Should I just put an inline glass 1A fast-blow fuse then instead of blade fuse? Many thanks
  10. J

    USB 5V power from 12V car supply

    So a 1A mini blade fuse should do the trick?
  11. J

    USB 5V power from 12V car supply

    The 12v to 5v converter i'm looking at is like this: not sure if it will have a fuse inside that housing. So considering maybe to add an inline blade fuse maybe on the red wire. Is that ok? and what amp fuse would be recommended?
  12. J

    USB 5V power from 12V car supply

    So if converter is rated at 3A max, should I put a 5A fuse or a 3A fuse?
  13. J

    USB 5V power from 12V car supply

    Thanks Martaine2005
  14. J

    USB 5V power from 12V car supply

    I have a 12v to 5v(3A Max) converter. I'm planning to hook this to charge my Nexus Android tablet as part of a car in-dash install. My question is: The converter seems to be regulated in terms of voltage but the current says 3A max. Therefore there doesn't seem to be any form of current...
  15. J

    12V Car Camera

    I have a Reverse Camera taken from a Lexus which was being dismantled for parts. It has 4 pins and i'd like to use it on a project I am working on. I am assuming 2 out of the 4 pins will be related to power (ground and +12v) and the other 2 will be maybe the video cable. Is there a way using a...
  16. J

    Multiple 12V batteries in Parallel

    I'm planning to build an array of 12V batteries in parallel to power garden accessories. The battery array will be charged by solar panels. Should i go for deep cycle 12v 100AH batteries?
  17. J

    Multiple 12V batteries in Parallel

    If i have four 12V 100AH batteries wired in parallel, am I correct in believing that the result will be 12V 400AH? whereas if i was to wire in series, then the result will be 48V 100AH. Is this correct? Thanks
  18. J

    Solar Panel and Battery Array Project.

    I've done a brief sketch of what I think the setup should look like, maybe that will help understand what I am trying to achieve and advise on how best to improve it. Heres the sketch:
  19. J

    Solar Panel and Battery Array Project.

    Hi Guys, I'm in the process of doing up my garden and need some help with the electronics aspect of the design. I will mainly be powering 12V LED lights in the garden along with a 1A pond pump. The plan is to run this of an array of 12V batteries. I'm thinking to start with maybe 3 batteries...
  20. J

    Breadboard help

    Thanks Steve
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