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  1. kellys_eye

    Audio Activated Relay - Circuit Help

    A common ground is necessary and harmless in this application.
  2. kellys_eye

    Mobility scooter

    You can't get more power by upgrading the controller - only the motor. If you want more speed AND torque then a bigger motor is essential. Is your aim a higher speed or faster acceleration?
  3. kellys_eye

    CO detector engine shutoff

    'micro' = microprocessor - the 'brains' of all engine management units. @Bluejets makes a valid point. Such levels are already monitored although not in the passenger compartment, but if you wanted to implement that function it would be far easier to add it to the code in an ECU than attempt...
  4. kellys_eye

    Mobility scooter

    If you want a short burst of additional power you could apply a higher voltage (say 36V) but only for a limited time and, preferably, monitored closely for temperature with the appropriate thermal cut-out. If you want a 'proper' increase in torque you need a different motor although 'torque' is...
  5. kellys_eye

    How can I connect this circuit to power?

    The red and black wires that are part-stripped are prepared for the 12V supply source. Those two wires (red/black) seem to go to the device shown above which will be a 5V regulator. Use an in-line fuse in the supply feed - a 3A fuse should do.
  6. kellys_eye

    Can anyone ID this transformer?

    Yeah, the DC designation is a funny one..... but given it's a centre-tapped secondary we can assume a fullwave rectifier feeding either a capacitive smoothing circuit in which case the DC load capacity is going to be the stated 60mA and 350V DC out. With a choke input filter your DC will fall...
  7. kellys_eye

    Battery Level Indicator

    You can wire an op-amp as a comparator, set the detection level to whatever you wish and have the output transition when the measured voltage falls below the set voltage. You can an wire op-amp as 'window comparator' that has three states of output - too high, too low or 'just right'. Google...
  8. kellys_eye

    Best Low-Cost Home PCB Prototyping?

    From what I've read, milling machines are getting better by the week and coming down in price too. If you're not after sub millimetre tracks and/or interpin routing then a cheap mill 'may' do the job but I reckon you'd have to ask on a CNC forum for specific details. Given that the 'pro's'...
  9. kellys_eye

    Best Low-Cost Home PCB Prototyping?

    I suggested that I'd get them from a Chinese supplier - what YOU do I couldn't give a rat's arris. There are just two popular basic home manufacturing methods that produce acceptable results - UV exposure and laser transfer (iron on). Both methods are well documented, easy to achieve and...
  10. kellys_eye

    Programming Languages

    1. Yes - but no reason why you can't add to your knowledge by including others 2. EPROMs, EEPROMs etc i.e. any memory-capable device 3. All of the above 4. Get a selection of the most commonly used devices and learn their architecture. C++, being a 'transportable' programming language means you...
  11. kellys_eye

    Best Low-Cost Home PCB Prototyping?

    You say.... 10 pcb's per day is stretching 'home manufacture' somewhat. In fact I'd consider that a mini-manufacturing outfit! The standard UV exposure box or Laser Transfer method is what I use - maybe, on average, 3/month - and even then I find it a PITA...... if I was more patient I'd get...
  12. kellys_eye

    Car battery jumpstart gadgets

    One good description of the issue I saw was: take one sheet of A4 paper (210x297mm) total area 62,370mm^2 to represent the global atmosphere. draw a square of dimensions 0.25mm x 0.25mm (basically a fullstop using a ball pen) - this represents the whole of the CO2 in our atmosphere. And ONE...
  13. kellys_eye

    Best Low-Cost Home PCB Prototyping?

    All you'd end up with is a routed (or etched) circuit board, un-drilled and with no solder mask and no printing and for multiple boards, presumably for sale? these are not options you can forgo. With the already-available low cost options for 'professional' pcb manufacture (often very little...
  14. kellys_eye

    CO detector engine shutoff

    Show your schematic. The flip-flop solution should be working.
  15. kellys_eye

    Help sourcing a switch.

    The 4066 is a quad switch with control inputs http://www.ti.com/lit/ds/symlink/sn74hc4066.pdf
  16. kellys_eye

    Car battery jumpstart gadgets

    No; global warming exists and, in the absence of irrefutable evidence to the contrary, is a natural effect that we have no control over. Show me the irrefutable, empirical evidence to the contrary and I'll consider changing my position. As an indication to your own so-called understanding of...
  17. kellys_eye

    Omron 24 VDC power supply Mosfet and diode replacement

    Do you have the facility to apply AC to the input as a variable supply? Such a source is very useful when it comes to SMPS repair work. If not then perhaps you have a transformer that has a couple of low(ish) secondaries you can series-up....? Have you checked the voltage divider on the...
  18. kellys_eye

    Taylor Electric valave voltmeter model 172A-schematics/service manual

    Could be they don't acknowledge the voltage regulator as a 'valve' although it looks like one. Shame you don't have the original operators manual - perhaps it specifies for horizontal use only???? <-- yeah, I know, it sounds silly.....
  19. kellys_eye

    Is this circuit fit for purpose if used on a 12vdc pump?

    The LOWER diagram is correct for polarity.
  20. kellys_eye

    Can you please help me with a Multimeter DT9205A problem

    They're around $5 each new...... Actually, I'm after about 10 of them.... can't find the 'old style' versions any more :(
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