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  1. duke37

    Norslo relay Help! Replacement

    I expanded the picture, it is definitely a dash, not a wiggle so as you say, probably DC but why not say so?
  2. duke37

    Norslo relay Help! Replacement

    If the 24V~ is a wiggle, then the relay could be 24V AC. You can check this by looking at the pole piece which will have a copper ring round half of it if it is AC. What is wrong with the relay/ If you are stuck, I may be able to find some contacts from a 240V AC Norslo relay. Edit The one I...
  3. duke37

    simple fm receiver

    BF199 25V 25mA 500Mhz BF255 20V 30mA 260MHz So the BF255 is similar but somewhat slower and it may not run at high frequencies.
  4. duke37

    Digital programmable CDI ignition for 2-stroke engines

    1. There does not need to be an RPM sensor, you will need a sensor to determine the crankshaft position and then calculate the RPM from this information. 2. The high voltage from the coil(s) goes to the spark plug with a wire with very thick insulation. You have to decide whether to use...
  5. duke37

    Building a power monitor

    The voltage input will be similar for all outputs, it is the current which differs. Thus one voltage reference would be adequate but a current transformer would be necessary for each output.
  6. duke37

    simple fm receiver

    Oh yes it is! Look up Wikipedia superregenerative receiver. The circuit oscillates at two completely different frequencies and detects FM by slope detection. The output is a form of pulse width modulation. Like I said, I do not understand it. This must be one of the most complcated circuits made...
  7. duke37

    Digital programmable CDI ignition for 2-stroke engines

    The project is complex and it may be too late to start unless you work hard at it. You will need to split the project into its sections and get each to work before combining them into one unit. Power supply without spikes Spark generation. Capacitor discharge or coil switchiing Crankshaft...
  8. duke37

    Building a power monitor

    If you are going to do complex calculations, then you could consider multiplying the current by the voltage so that power factor is taken into account and true power is obtained. The voltage could be obtained by a low voltage transformer for isolation.
  9. duke37

    simple fm receiver

    I think this is a superregenerative circuit which oscillates locked to the input signal. I do not understand it! The sensitivity is high and was used when a valve (tube) could cost a weeks wages.
  10. duke37

    12v fans, simple question

    To limit the current you could use one fan only or put the two fans in series so that each fan would see 6V (and run slower).
  11. duke37

    Replacement for a microcontroller

    You may be able to use a voltage to frequency converter to shift the frequency to a higher value. Then use the computer audio input and a program (audacity?) to regenerate the basic value and display the data.
  12. duke37

    Building a power monitor

    I would consider rectifying the signal it you do not want true RMS values. In any case, you are not taking power factor into account. Put the secondary of the current transformer through a bridge rectifier which then feeds the burden resistor, paralleled with a capacitor. The current...
  13. duke37

    Ideas For Delayed Bright Spark / Pop Sound Static Gap Capacitor

    The normal way to deter deer is by an electric fence. A spark will produce little light, a discharge tube is much better. Any rapid voltage change can be fed to an audio amplifier to produce a crack.
  14. duke37

    electric pulse counter

    I had a look on ebay for 'electronic counter' and found some very cheap counters intended to be mounted on a wrist. These need a button to be pressed so you would need to open one up and connect a pair of wires to your switch. I presume the counter runs on an internal battery. Another phrase...
  15. duke37

    Trouble with LM567

    And here it is if you are in Australia!
  16. duke37

    Voltage-controlled switch

    What is zero? Do you mean less than 1V or less than 0.0001V? A perfect capacitor loaded with a resistor will in theory never get to zero volts.
  17. duke37

    Measure time when ground connection is lost ?

    I believe there are pads that can be placed to detect walkers. Using one of these would eliminate the need to wire up the victim. Trafic detection is sometimes done with a fluid filled tube and a pressure detector. Wahing machines have sensitive pressure switches to detect if the water level is...
  18. duke37

    Power Supplies Problem

    I assume these are two seperate power supplies. The first one could have a fuse blown or a bad connection somewhere. The second may have a faulty potentiometer. You will need to get an idea of the type of supply to narrow the fault down and maybe draw your own circuit diagram. Some pictures...
  19. duke37

    need some help..

    If all else fails, read the instructions.
  20. duke37

    Ceiling fan speed?

    My thought is that the voltage is reduced and the speed drops. This could overheat the motor with a constant load but in the case of a fan or central heating pump, the torque is proportional to the square of the speed so comes down rapidly as the speed drops.
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