Variable frequency pulsed generator

Discussion in 'General Electronics Chat' started by BillHil, Nov 3, 2013.

  1. BillHil

    Thread Starter New Member

    Nov 3, 2013
    I am a beginner to electronic field. I am trying to build a variable frequency pulse generator. I am doing some basic research on the relationship between frequency, pulse rate, and bone growth. I want the frequency pulse generator to be in the 1.0 to 500.0 Hz range with the ability to vary the pulse rate per second from 1 to 100. I want the frequency probe to have a DC voltage from 5 to 12 volts and the frequency probe tip to be no larger than 2 mm. Any help you can provide would be appreciated. Thank you.

  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    What shape the pulses?
    What duration?
    What rise/fall times?
  3. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    Do you mean just one fixed voltage in that range, or a user-selectable voltage, or a ramped voltage?
    What current must the probe provide?
    What safety measures are mandatory to protect the patient?

    If, for example, the pulse frequency is 1Hz you can't have a repetition rate > 1 per sec. Can you specify your requirements more clearly?
  4. wayneh


    Sep 9, 2010
    Are there references you read that inspired you to dabble in this? I mean, is there a specific device or treatment regime you want to replicate?

    We need more details to be able to offer better advice.
  5. adam555

    Active Member

    Aug 17, 2013
    The simplest way will probably be using a 555. You can use this as a starting point:
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    If you want to experiment with using the thing (not building it!) you can buy cheap signal generators on Ebay for under $50 that vary the frequency and also have a digital display to show you the exact frequency (to be scientific).

    Search Ebay for "signal frequency generator LCD display". :)
  7. wayneh


    Sep 9, 2010
    A related approach would be to use a smartphone as the signal generator (there are free apps for this) and then a suitable op-amp amplifier to create the voltage and/or current signal you want from the smartphone signal. This would save you from creating your own tone generator. That's not hard, but getting the accurate and precise output would be tough for DIY.

    I think we're still waiting to learn what the output signal is. Do you just want a voltage on your electrode, with no concern for current? Do you want your pulses all the same polarity? (There are arguments that reversing polarity increases the effectiveness.) Do you intend to hold treatments at a fixed frequency and duty cycle? (Some treatments automatically alter the frequency to avoid "burn in".)