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  1. Alec_t

    How to delay the relay

    In view of that inconsistency, this is beginning to look like a poor (high resistance) connection somewhere. Are the relay contacts adequately rated for switching heavy DC current (many are not)? Is your wire gauge man enough for the job?
  2. Alec_t

    Sensor for solar irradiance

    If you do that, be careful not to detach a wire from the cell itself. Attempts to solder a wire back on can be frustrating, as the cell metallisation is easily destroyed. Don't ask me how I know :D.
  3. Alec_t

    looking for feedback on feasability of this idea...

    Okay. But in my garden lights the solar cell is the day/night sensor :).
  4. Alec_t

    Portable earth test

    Welcome to EP! Unfortunately, just having earth continuity isn't enough. The earth connection has to be capable of passing fault current and needs to be low resistance so that the current doesn't cause the equipment potential to rise to a dangerous level. The earth test therefore needs to be...
  5. Alec_t

    Ohm resistance controller

    What wheel/road speed sensor do you have? What sort of servo? Can you program a MCU to handle input/output signals?
  6. Alec_t

    small motors

    I'm with Bob. Running dry involves high friction which creates heat which causes expansion which increases friction which increases heat ......
  7. Alec_t

    Respectfully requesting audio related info.

    Tricky with a violin, or other instrument where the body is a sound-box, since adding the pickups coulld adversely affect tonal quality. Presumably not a problem with an electric guitar. Being a cheapskate (not a musician) I'd probably make some home-brew pickups for an electric guitar.
  8. Alec_t

    Missing Varistor on Coleman Powermate generator

    Has someone already had a tinker with the board? Definitely NOT. If you look at the datasheets for the two varistors you will see that their continuous withstand voltages both exceed your power supply voltage, but differ from each other. I don't know why that is; perhaps a belt-and-braces...
  9. Alec_t

    Power limiter on kids ride on car

    Welcome to EP! The cut-out is there for safety reasons. If you bypass it the motor could overheat with prolonged use, even if it can survive briefly.
  10. Alec_t

    looking for feedback on feasability of this idea...

    I suspect the photocell in a garden light is way too small to provide enough energy during the day to sustain the required heating during the night. And of course if you replaced the cell with a thermistor you'd lose the solar energy harvesting. Either way, an alternative source will be needed IMO.
  11. Alec_t

    Convert uneven pulses

    I doubt it. The pulses would probably be driving a chunky uniselector at the telephone exchange. Unlikely a few mS of bounce would affect it.
  12. Alec_t

    Missing Varistor on Coleman Powermate generator

    That electrolytic capacitor bottom left of the pic looks bulged and leaky? If so it could be the cause of the failure. Not if it's connected across the power rails!:eek:. Can you be sure the 'missing' varistor was ever there?
  13. Alec_t

    increasing voltage or current

    Q1 is acting as what is called a 'low-side' switch. If it were between the supply and the diode it would be a 'high-side switch', but would be more dificult to control with the 1.8V signal.
  14. Alec_t

    200vdc 1A supply, adjustable 180-220vdc

    LEDs should normally be current-driven, not voltage-driven. Wouldn't a conventional constant-current LED driver, albeit with a current which you can control, suit your needs?
  15. Alec_t

    Android automobile gauges

    I can see it being relatively straightforward to sense engine rpm, roadwheel rpm, MAF, ignition timing and engine/ambient temperature, but without fuel injection how will you sense fuel consumption?
  16. Alec_t

    How to delay the relay

    Are you sure you allow enough time for the motor to travel to its limit position before reversing it? I would guess it has a leadscrew drive and could take a second or two to shift the spool. Maybe the internal limit-switches allow reversal only after the limit position has been reached.
  17. Alec_t

    Respectfully requesting audio related info.

    You will presumably need a separate pickup for each string. What pickup(s) is/are currently used? How many strings?
  18. Alec_t

    Is it possible to use a stepper motor without a micro-processor ?

    Googling "stepper driver IC" gives lots of hits for suitable control chips.
  19. Alec_t

    Linear power supply design circuit [help]

    If D1 is a zener diode (it's shown as a normal diode) then RV1 will control the input voltage to the 338. R2/Q2 provide fixed current-limiting.
  20. Alec_t

    36v 7a class D bicycle trailer system... amps & capacitors?

    0W would be ideal :D. I share Bob's misgivings. If you want a loud noise (= loud 'music') just use headphones. That way you damage your own ears and nobody else's.
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