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  1. Alec_t

    Complex (to me) heater project, 12v

    You're welcome. Time now to think up your next project :).
  2. Alec_t

    Automobile charging circuit light circuit

    If you don't actually connect it via the ignition switch then you have to find some other way to isolate it until the ignition key is turned: otherwise the battery drains via the D winding of the generator.
  3. Alec_t

    Letting current flow only for an amount of time ?

    Do you mean the detector output rises from 0.5V to 9V (i.e is a positive-going pulse edge) when smoke is detected? If so, to trigger a 555 timer IC at pin 2 you will need a transistor stage to provide a negative-going pulse signal.
  4. Alec_t

    Complex (to me) heater project, 12v

    Unless the steel walls are well insulated, e.g with many cm of fibreglass or expanded polystyrene, you are going to lose a lot of heat through them. My calcs show you'd need ~428W to maintain a 4C temperature difference between the inside and outside of the container, just to cover that heat...
  5. Alec_t

    Complex (to me) heater project, 12v

    That's not a room: that's a cupboard :). Assuming 100% effective insulation (no heat loss at all from the room!), it would take about 3W of power to raise the temperature of just the air by 8C over three hours. The U-value of common building materials is around 2W-4W /m^2. Some more questions...
  6. Alec_t

    Adding "on" light to 240V thermostat

    Simply wiring the neon (with series resistor) across the thermostat switch would provide an indication; albeit non-ideal in that the neon would light when the switch opens rather than closes.
  7. Alec_t

    Complex (to me) heater project, 12v

    Welcome to EP! The physics is all important and should be your starting point to see what's feasible. 1) How big is a 'small' room? 2) What percentage of the room is occupied, and by what? (The thermal capacity of the contents needs to be accounted for, since the contents also have to be...
  8. Alec_t

    Measure WATT of LED

    :confused: What prior posts? I responded to post #1 in a 'Repairs' forum; not in a 'Homework help' forum.
  9. Alec_t

    Aqualisa Lumi 10.5kw no power

    In the UK these showers have their own dedicated 60A cable from the incoming single-phase mains distribution box.
  10. Alec_t

    Aqualisa Lumi 10.5kw no power

    Any unexpectedly low impedance in series with the inductor could cause a current surge sufficient to blow it. So now you need to locate such an impedance :(. The pics don't seem to show anything which would justify the high price of the unit. Has it got gold plumbing? :).
  11. Alec_t

    Is there anything useful in a photocopier?

    At the very least, harvest the nuts and bolts. Wiring looms and connectors can be handy. Relays, power semiconductors, through-hole components with enough leg length to be re-usable. I wouldn't bother with electrolytic capacitors, which may have died from old age anyway.
  12. Alec_t

    I want a badge!

    I think having 'Superuser' in you avatar diqualifies you from getting a 'Complete Utter Loser.' badge, but your efforts so far haven't had the desired effect so you do meet the criteria for 'Apprentice Loser' on that ground :).
  13. Alec_t

    Coil with iron core as a generator

    Given that the average power output of an average human over a working day might be only 100W, most of that would be used in propelling your bike. Let's say you have a spare 10W or so for powering your generator, and the generator efficiency is 10% (including conversion to a steady 5V for...
  14. Alec_t

    20 Watt LED Dimmer Circuit diagram

    I suggest you read through the whole thread, make a list of the questions you have been asked, then answer each one carefully. Without those answers any circuit design we come up with would be unlikely to work properly. If you don't know the answer, say so. At least provide a link to the source...
  15. Alec_t

    Coil with iron core as a generator

    Individual coils will be far easier to wind. Core pole piece geometry and positioning as close to the magnet path as possible will be critical for maximum efficiency. I'd forget about the phone charger if I were you. It will take a month of Sundays to fully charge a phone by pedalling ;).
  16. Alec_t

    Electronic timer motor

    There are two time periods involved: 1) the delay (few hours max) before the motor switches on, 2) the period the motor stays on. What triggers the start of the delay? Is this a single trigger, or repeated?
  17. Alec_t

    Help me draw this circuit's diagram

    :confused: According to post #1 you built the circuit. Now you say you bought it?
  18. Alec_t

    DIY Guitar Pedal, not functioning at all, advice please.

    That looks like a wiring error, assuming the guitar pickup directly drives the pedal. If it merely reduced the volume it might be that the pick-up needs to drive a higher impedance load than the pedal input provides.
  19. Alec_t

    Charging a LiO Battery with a solar panel for Ebike

    G'day. Welcome to EP. What is the panel spec (open and short circuit current, watts)? Methinks you will need a pretty big panel area to get any useful amount of charge into the battery. Option 2 would have the advantage of proper/safe charging of the battery. You don't want to be the cause of a...
  20. Alec_t

    Beginner question: How do I let a 12v 36w current through only when a 1v signal comes from a source?

    Set the Ohms range to include the expected value of a resistor under test. Measure with the probes first with one polarity then with the opposite polarity (in case there is a semiconductor junction, somewhere in the circuit, in parallel with the resistor). This test is not conclusive if there is...
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