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  1. AFex54

    4066 switches leaking in sample and hold circuit?

    What are the negative effects of bouncing in this circuit? I wouldnt think it would pose much of a problem for my application
  2. AFex54

    4066 switches leaking in sample and hold circuit?

    yes the switch is a 4066 CMOS switch running on 9V , being triggered by 9V. I have not yet added anything to prevent contact bounce
  3. AFex54

    4066 switches leaking in sample and hold circuit?

    the circuit it sampling voltages from 0V to 9V from a potentiometer voltage divider and nope I dont need 1μs but 1 ms is a bit too long for my liking. the hold time is completely variable, the voltage will be sampled manually with the SPST button I just realised i made a mistake and the...
  4. AFex54

    4066 switches leaking in sample and hold circuit?

    other than with a spdt, cos mechanical switches are pretty much the extent of my knowledge on electronics. I used a 2k resistor and now the 4066 is working properly, thanks! but now I have a second smaller issue, to generate a short trigger for the switch from a 9v pulse im using this...
  5. AFex54

    4066 switches leaking in sample and hold circuit?

    yup, though I didnt know how to alternate between ground and 9V other than using a SPDT switch haha
  6. AFex54

    4066 switches leaking in sample and hold circuit?

    ok thanks, I did a bit of reading and Im pretty sure what I need is a pulldown resistor, to keep the input low even with nothing connected. Do you know what value resistor I should use?
  7. AFex54

    4066 switches leaking in sample and hold circuit?

    Hi, I'm having a problem when using a 4066 switch in my sample and hold circuit, when I used a mechanical SPST switch to test the S&H circuit when it was on the breadboard it worked great so I know there's nothing wrong with the circuit itself. when I use the 4066 switch it seems to be leaking...
  8. AFex54

    sample and hold pulse source?

    but you see I already have 4069s , 25 of them! from what ive read a Schmitt trigger has a threshold band rather than a centre threshold point like the standard hex inverter , I cant see how this would make any difference when digitalizing a simple 9V spike. could you explain why a Schmitt...
  9. AFex54

    sample and hold pulse source?

    Hi again, Ive only gotten to this stage of my project now and I like this circuit because If I add a SPDT that can bypass the differentiator I can 'track and hold' too! anyway all im wondering about is making the filtered pulse more digital, I have 4069 hex inverters , would these be ok?
  10. AFex54

    A means of closing a JFET switch with a postive voltage?

    I have some free time so Im finishing this up today, everything is working great now I just need to build on it a veroboard . will let you guys know how it turns out P.S would it be ok to just use 0.1μF bypass caps for all the ICs? this is at least a 'better than nothing' decision but maybe...
  11. AFex54

    A means of closing a JFET switch with a postive voltage?

    thats a shame cos I already own 10 of these things and I cant see why I would ever be using a supply lower than 9V... infact from all the trouble 9V has caused me so far I'll be going higher! I wonder could I simply lower the supply voltage to below 8V with a diode/resistor and run it with that?
  12. AFex54

    A means of closing a JFET switch with a postive voltage?

    so my S&H is finally working and I can continue my project! my synth also has another S&H that will be used in the traditional way to make some cool synth effects. Im wondering about those unsuitable rail-to-rail Op Amps that a I bought a few weeks- the TLC2264. the datasheet says the maximum...
  13. AFex54

    A means of closing a JFET switch with a postive voltage?

    I dont have the schottkys now but Im after testing the voltage drop of a standard 1N914 from 0-9V and I doesnt go over 0.4V. that should be ok but i wonder If I did use schottkys would the drop be almost non existent (0.1V)? anyway I will just use the 1N914 since I own lots of them already and...
  14. AFex54

    A means of closing a JFET switch with a postive voltage?

    I have tested with the TL074 and polystyrene cap by manually sampling with 2 wires and it works good. https://www.electronicspoint.com/attachments/updkb2-png.21470/ the diodes for the CV in green would be the schottkys.
  15. AFex54

    A means of closing a JFET switch with a postive voltage?

    So I will use a CD4066 for the sampling switch, For the schottky diodes, I think im looking for one with maximum values as close to my supply as possible for maximum efficiency and minimum voltage drop. I looked through a load of them and this SD101C has the lowest, 40V and 30mA. Also a...
  16. AFex54

    A means of closing a JFET switch with a postive voltage?

    ''I know I explained this in that post where I quoted myself, did you see?'' I sound like im talking about a post that was made a week ago when I just meant post #68... I think Ill go to bed now haha
  17. AFex54

    A means of closing a JFET switch with a postive voltage?

    I know I explained this in that post where I quoted myself, did you see?
  18. AFex54

    A means of closing a JFET switch with a postive voltage?

    Ok so I decided what I will do is build the sample and hold with a TL074 , I already explained how this will work here: (you can actually see visual evidence of the low voltage cut off in the NT demo video at this point) If the S&H works well in the finished synth then I will purchase the...
  19. AFex54

    A means of closing a JFET switch with a postive voltage?

    If i were to tune it to a typical musical scale the key voltages would only be a few mV apart for each note. btw there are only 24 keys, 10 of them have 2 pots for polyphony P.S Im glad you questioned me though because it made me query the NT being ''18mV per octave''. there is no way this is...
  20. AFex54

    A means of closing a JFET switch with a postive voltage?

    EDIT: this post is null and void, you can ignore :) I just read this here: ''The Arduino board contains a 6 channel (8 channels on the Mini and Nano, 16 on the Mega), 10-bit analog to digital converter. This means that it will map input voltages between 0 and 5 volts into integer values between...
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