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  1. Kiwi

    Choosing Wire Gauge

    I use these formulas for selecting wire size for automotive applications. Volt drop = (0.0183 x L x A) / CSA CSA = (0.0183 x L x A) / Volt drop L - length of wire in metres(return length) A - Amps CSA - Cross Sectional Area of wire in mm2 0.0183 - copper resistivity constant. (Often see...
  2. Kiwi

    Help selecting the correct Diode

    Yes and Yes. Schottky diodes may be better for this application due to their slightly lower voltage drop, but are not an absolute requirement for simple circuits like this. General purpose silicon diodes may get slightly warmer, but will still work well in this application. There must be...
  3. Kiwi

    Building code: Recessing aluminum PS in a wall

    Suggest that you contact a local registered electrical contractor as rules vary from place to place. There may also be insurance and legal issues if you do it yourself.
  4. Kiwi

    Help selecting the correct Diode

    Here is a nice video on diodes; I only keep two diodes for these sorts of simple jobs; 1N4007 1A, 1000V 1N5408 3A, 1000V I have never had an issue using either of these diodes. I also often solder them inline and put heatshrink over them.
  5. Kiwi

    Is this circuit possible?

    Your circuit is nice and simple. It will work fine. The only suggestion I would make is to put the switch in the positive line, not the negative line. If you look at most circuit diagrams you will see that the negative is usually drawn as the common. Having a constant common negative makes...
  6. Kiwi

    Do NOT do ANY of this! Safety first lol

    My thoughts are that he knows exactly what he is doing. Could be an educational video to get students to actually watch, rather than just dropping off to sleep at another ####### safety lesson. Very clever.
  7. Kiwi

    How to delay the relay

    This might help. [ MOD Note: got rid of that annoying pdf file ;) ]
  8. Kiwi

    wiring a LED lit rocker switch

    Switch needs to be in the positive line from the centre tip of cig plug.
  9. Kiwi

    Output Voltage Selector

    What about old school diodes?
  10. Kiwi

    Is this actuator really 12VDC? Could it be 24V?

    My first suggestion would be to try the actuator with a fully charged 12v car battery. The power supply voltage may sag when the load comes on, current will increase, and supply voltage may not recover. A car battery can deliver a very high load without the voltage sagging by very much. You...
  11. Kiwi

    ElectronicsPoint Facebook Group!

    Facebook, who needs that for this forum? This forum works very well as it is. I don't see any need to join the social media rat race. As KJEAD posted "... it would be a non-solution to a non-problem".
  12. Kiwi

    Automotive abs 3 wire sensor

    It is very common for automotive sensor output terminals to read +5v when disconnected. The ECU will have an internal resistor pulling the sensor voltage high. The sensor will pull the voltage down depending on applied pressure etc. Connect a 5k or 10k potentiometer to the plug and read the...
  13. Kiwi

    Very Fine Cable?

    I usually use tinned 5A fuse wire.
  14. Kiwi

    Relay help.

    Why are you switching the low current memory battery supply? In a vehicle this is live all the time, whether the stereo is on or off. There are a few different ways that car stereos operate; 1 - Low current constant battery supply for memory only. High current accessory/ignition supply to...
  15. Kiwi

    DC-DC Voltage Step Down Module

    NMNeil spotted the low voltage of the input capacitor on the bottom module. This was the first thing I noticed when I saw this in our local electronics store catalogue. The top photo I found on Aliexpress for comparison and has a 50v input capacitor. It has a few issues with component...
  16. Kiwi

    DC-DC Voltage Step Down Module

    Afraid not. ;) :oops: Hope my old English teacher never reads the original post. Is there any way to go back and edit your mistakes?
  17. Kiwi

    Digital potentiometer ?'s

    "Fuel gauge is programmable for Ford, GM, Chrysler, VDO and universal aftermarket senders." I would guess that the initial setup would be something along the lines of hold the sender at empty and then move to full. There might be a button or something on the back you push to do this. The PIC...
  18. Kiwi

    Digital potentiometer ?'s

    Are you sure that the fuel gauge on their 5 gauge dash is not programmable to suit your sender?
  19. Kiwi

    DC-DC Voltage Step Down Module

    Above are photos of a couple of DC-DC voltage step down modules using a LM2596S. Both are rated at 3A with 3v - 35v input, and 1.3v - 34v output. One of them has what looks to me like a possible problem? There are probably more than one possible problem with these modules. Your mission, if you...
  20. Kiwi

    op amp supply voltage

    From memory +5v to +15v is the preferred supply voltage for the 741.
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