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  1. Alec_t

    1600W heat using weight sensor

    Lever-operated microswitch
  2. Alec_t

    Lithium ion polymer batteries

    They power electrical/electronic things and are used in most places (apart from where you live, apparently!).
  3. Alec_t

    real time simulation can't be run

    I don't use PROTEUS, but it looks like there are several 'logic contention' issues. Have you tried adding a few parasitic very low parallel capacitance and/or series resistance values at the net nodes concerned? That may be enough to break a logic dead-lock. Or perhaps you need to close all...
  4. Alec_t

    90 degree turn servo and controls

    A suitably programmed MCU could take care of the timing functions and actuator driving. However, you would need to provide an impact-buffering mechanism between each target and its actuator (/servo) to reduce impact forces; otherwise the actuators will have a short life.
  5. Alec_t

    How to control the speed of a 24vdc pump from circulating water temperature?

    Googling "pipe thermistor" brings up several clip-on types.
  6. Alec_t

    Water level Controller - Arduino Based

    Agreed; but all the indicator LEDs are in series with the probe/water resistance, like this: Rx is likely to be tens of k, so the LED s won't light brightly.
  7. Alec_t

    Water level Controller - Arduino Based

    LEDs D7-11 won't light if they are in series with the water-level sensor probes of the type described.
  8. Alec_t

    Interpret the circuit for a Carbon Monoxide detector

    With the circuit shown you would have 5V as the +ve rail. For the heating cycle you would turn on the top (PNP) transistor for 14ms every 1 sec. Due to the Vce voltage drop there would be 4.8V across the heater (terminals 1,4). For reading the sensor output you would turn on the lower (NPN)...
  9. Alec_t

    Water level Controller - Arduino Based

    Increase R6-9 to 100k.
  10. Alec_t

    inverter transformer parameters

    This may be of use. Welcome to EP!
  11. Alec_t

    Frequency dependent resistor in PSpice

    Can't you just right-click on the resistor value in the schematic and set the value to {2*frequency} ? Then add a directive .param frequency=3meg (or whatever).
  12. Alec_t

    Frequency dependent current controlled voltage source in Pspice

    Don't know about Pspice, but for LTspice you could put a directive on the schematic, e.g. for a frequency of 60Hz the directive would be .param R_CM = 2*60.
  13. Alec_t

    clock charing usb devices

    Welcome to EP! I doubt the clock wind-up mechanism stores enough energy to do much charging :(. According to Wikipedia, "adults of good average fitness average between 50 and 150 watts for an hour of vigorous exercise." Clock-winding is hardly a vigorous pursuit, so assuming you can wind up the...
  14. Alec_t

    Potentiometer Value and Rating?

    ... and a snip at only £165 !
  15. Alec_t

    Building generator and motor

    Your biggest problem may be sourcing and shaping suitable silicon steel laminations for the coil cores/poles. Do you have a source? As for the windings, those will depend on the size and power rating of the motor/generator.
  16. Alec_t

    spice model

    Welcome to EP! Can't you use a model for some other adjustable boost regulator IC?
  17. Alec_t

    12V adapter + resistor = 9V adapter?

    Why not buy a 9V adapter? A couple of diodes could then be used to steer power from that or the 9V battery as required, or a switched jack would do the job.
  18. Alec_t

    Centrifuge PCB

    Is the centrifuge lid static, or can it be modified to be static? If so, that would avoid the need for slip-rings/balancing.
  19. Alec_t

    How to control the speed of a 24vdc pump from circulating water temperature?

    If you wanted a home-brew solution, here's my offering for a thermistor-controlled PWM speed controller: The sim plots show the PWM drive to the motor, and the motor current, as temperature is swept from 0C to 100C.
  20. Alec_t

    How to control the speed of a 24vdc pump from circulating water temperature?

    There are plenty of DC motor speed controllers advertised on the net. Most have a potentiometer to set the speed. Perhaps you could replace the pot with a thermistor in series with a trimmer rheostat.
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