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  1. duke37

    Remote Distance Sensing

    If you measure the increments and sum them, you will get the right answer unless once you turn a corner you get a reflection from a wall when the increment could jump. To do this you will need to move the sender to a new location for each increment.
  2. duke37

    Rectifying an audio signal

    Horowitz and Hill (p120 in my 1980 copy) give details of two absolute value circuits if you need something more fancy. I could sketch these out if you wish, the book will not fit on my scanner.
  3. duke37

    Remote Distance Sensing

    If you havn't got line of sight, then any response will have to have gone round an extra, unknown distance. With a 40kHz signal, you may need to detect the first or second cycle depending on the accuracy needed.
  4. duke37

    Old Auto Battery Charger

    Looks about right to me. Car alternators are set between 13.8 and 14.4V. A simple charger will overcharge a battery if left to its own devices, just leave it to charge up to 14V.
  5. duke37

    Voltage limiting without altering waveform

    It is intended to view 400V AC so should be designed for 1kV input unless a divide by 10 probe is used when 100V input should be adequate. Perhaps a divide by 100 probe would be best. A diode clipper could come after the op-amp.
  6. duke37

    Signal help

    I suggest that you start with switching leds on and off, then make some audio amplifiers. When you have experience in this area, try to make a radio receiver. The TIP147 is a PNP Darlington transistor. It may be possible to get this to work at 200kHz. I have a feeling that you are taking...
  7. duke37

    Signal help

    The wavelength of a signal is 300/f(MHz), so if you get your 555 reved up to 1MHz, then you will have a wavelength of 300m. For an aerial, a halfwave dipole consisting of a wire 150m long, fed in the middle would do the job. If you play with 1000MHz, the wavelength will be 300mm and any...
  8. duke37

    Signal help

    To think that it is easy to deal with these very high frequencies is delusional. The 555 can deal with perhaps 1MHz, CMOS 5Mhz and ECL over 100MHz but to get up to 1000MHz very special techniques are required. It is impossible to wire up a test circuit because of the stray inductances and...
  9. duke37

    LED flickering with CC driver

    I do not do a vast amount of construction but I have never known of the case of a diode dying. In my experience, they are either living or dead. Diodes can be killed by switching them on into a large capacitor but the 1N4007 is robust and should stand this. Just don't try it with a 1N4148...
  10. duke37

    LED flickering with CC driver

    The TI data sheet covers this, the ESR rises as temperature goes down, particularly with aluminium electrolytics, you can add as much capacitance as you like. They suggest adding a tantalum in parallel which is less influenced by temperature.
  11. duke37

    Voltage limiting without altering waveform

    I understood that you wish to make an oscilloscope using a sound card. If so, you will see if the waveform is clipped. You will need some complicated circuitry to automatically adjust the attenuator which I do not think justified and you will not know the attenuation which has been set. The...
  12. duke37

    What is this Vaporette?

    Googling indicates that this is a device for soldering SMD devices. A fluorcarbon is boiled to give a hot vapour and the circuit board is placed in this. The surplus vapour is condensed with water cooling. The temperature is closely controlled by the boiling point.
  13. duke37

    Voltage limiting without altering waveform

    I have not gone into the details of your circuit but it will not work since there is no current through the zener and you will need voltage offsets to get the fets to turn on at the right voltage. A voltage divider will have a top resistor and a bottom resistor. For your highest attenuation...
  14. duke37

    Voltage limiting without altering waveform

    I had finger trouble, lilit shoud be limit! If your attenuator has a resistor of say 100k from the signal source then two silicon diodes in series will limit the signal to about 1.2V in one direction. Two diodes in series connected in the other direction will limit the voltage with the...
  15. duke37

    Voltage limiting without altering waveform

    If your voltage dividers have high value resistors in them, then it is only necessary to lilit the voltage with some diodes. The wave form will be distorted but you will be able to see if it is clipped and, if so, increase the attenuation. Do you think it a good idea to put 400V anywhere near...
  16. duke37

    Wiring Permanent Magnet DC motor to Motor Controller

    Check that there is a connection between A1 and A2. Check that there is NO connection between either A1 or A2 and frame. Check that there is a connection between green wire and frame. If so, this is ground (earth). Power goes in to A1 and A2. You will need a DC motor controller of more...
  17. duke37

    Wiring Permanent Magnet DC motor to Motor Controller

    Do not connect anything to this motor until you find out what type of motor it is. It could be permanent magnet, series wound or shunt wound or even compound wound. Whatever you do, start out with a series resistor which can take the full motor current so that the current is limited. Do...
  18. duke37

    Inductor/Capacitor wireless audio

    http://en.wikipedia.org/wiki/Audio_induction_loop
  19. duke37

    Inductor/Capacitor wireless audio

    The 'lines of force' diverge as you move from the centre of the loop. If I remember right, a loop of side 10m will work reasonably well 2m from the loop plane. There is no way you can 'fire' a signal but you can alter the shape of the loop to put the signal where you need it.
  20. duke37

    Electronic Parts [Explained] pls..

    Or you can look at #5 where I explained it to you and asked whether you understood.
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