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  1. C

    Transistor switching on another voltage supply

    Alright fine 2am never read it properly regarding it can't share grounds... But why?
  2. C

    More efficient LDR "dark" switch?

    I thought i'd have a go at designing a low power circuit but i used a potentiometer as the ldr, so it may need swapping (lights when it's light ).. 3am and pretty wasted too, so forgive any oversights lol
  3. C

    Transistor switching on another voltage supply

    Opto's are over kill for this imho....
  4. C

    Transistor switching on another voltage supply

    Or better still, use an NPN power transistor voltage of 1v is too low for a mosfet , 12v + side to your device to power, eg 12v bulb and the other side to the collector and the emitter tied to ground that leaves say a 300ohm resistor from the 1v to base of the npn.
  5. C

    Need help : Steel conductivity vs LED

    Infact.... wire a second led up to the metal case but with the negative of led and series resistor... The fuse handles a dead short.. Red led lights for positive leak Blue lights for negative leak..
  6. C

    Need help : Steel conductivity vs LED

    You could just wire the positive side of the led to the case with a resistor light comes on there's a fault... Simple enough?
  7. C

    Need help selecting a LED Driver

    These?
  8. C

    Need help selecting a LED Driver

    How many square dies are on your "3w" led? Take a 10w (3x3) each die handles roughly 1w, if you have 1 square and not 3 of them i doubt it's 3w.. cree's make 5w single dies, only 3watt ones i've seen have 3 sections..
  9. C

    Triacs

    A simple light dimmer circuit... If it does not work i'll swap it out then, but i'll give it a shot, the old triac was shorted and the fuse blown (for a 240vac halogen style 60watt bulbs
  10. C

    Triacs

    Are these two interchangeable? I have the bta12 but not 06 on a blown board...
  11. C

    How do you not run outta batteries?

    Oops missed your reply... Yeah use the 6v wall adapter, is the plugpack heavy or light? If it feels solid and heavy it uses a transformer which for electronic use is perfect... I don't think i could handle using a switch mode psu on electronics you handle with bare hands, yes there's a high...
  12. C

    How do you not run outta batteries?

    Buy a small 12v lead acid battery for alarm systems.. I then charge it with an lm2596 switching regulator from a 3amp 19v charger float charging the battery to 14.2ish voltz (float charge it) I then charge smaller batteries from that .. Ebay has a lot of cheap nimh batteries 5 bucks will get...
  13. C

    Need help with a power supply/battery circuit

    If you used a phone it would require a sim card? So does the tracker... (how else will it report your location to the server?)
  14. C

    Name that switch!

    Lol you'd have to do a lot of teeth grinding!
  15. C

    Name that switch!

    Fair enough... If you were able to use a small plastic tube to clench on without choking, maybe a pressure sensor like the one used in washing machines to detect when water fills up, tricky. But with the piezo it's not really energy harvesting as the tiny signal is amplified...
  16. C

    Will this switching down-regulator protect at all against short-circuits?

    200 - 500ma fast blow fuse then...
  17. C

    Will this switching down-regulator protect at all against short-circuits?

    Fuse should be rated 30 - 50% higher than the max current the quad copter pulls or the fuse might blow from just using it.....
  18. C

    Name that switch!

    My thought... A piezoelectric mic could be stuck on with tape to the side of your mouth/jaw the output fed to a small opamp which in turns slowly charges a capacitor which is bled to ground... So for example just clenching will fire a spike but not enough to charge the cap, when you begin...
  19. C

    Will this switching down-regulator protect at all against short-circuits?

    At the time the webpage you linked was dead for me... The lm2596 is a cheap common switching regulator, probably inside the device you linked to... The battery is?
  20. C

    Will this switching down-regulator protect at all against short-circuits?

    If the leads going to the tracker cross, the lm2596 will supply as much current as possible until the chip warms up to the point it will burn you if touched, at which point a few seconds it will begin reducing current .. Either the wires begin melting or the battery gets drained...
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