Variable Capacitor Configuration Proteus

Discussion in 'General Electronics Chat' started by Shayan22h, Nov 30, 2012.

  1. Shayan22h

    Thread Starter Member

    Oct 24, 2012
    30
    3
    hey guys I have made a timer with ne555 in proteus, i wanna use a variable capacitor instead of C4 my capacitor so then i can get different output as i change my input capacitance, the problem is whenever i wanna use variable capacitance it gives me an error message that i should configure my variable capacitor so i was wondering if u could please help me :) ?
     
  2. absf

    Senior Member

    Dec 29, 2010
    1,492
    372
    Not all components in proteus can be simulated. Many are just for drawing schematics and PCB footprints.

    So if you must use variable caps, you can always do in this way....

    Allen
     
    PackratKing and Shayan22h like this.
  3. Shayan22h

    Thread Starter Member

    Oct 24, 2012
    30
    3
    Thank u so much, it is really smart, i dont know why i couldnt think of it at the first place,
    cheers
    :)
     
  4. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    Can't proteus use a parameter for the capacitance, so that you can sweep through the values? All spice simulators I know of can do this.
     
    Shayan22h likes this.
  5. absf

    Senior Member

    Dec 29, 2010
    1,492
    372
    Yes of course, but not on a variable capacitor.

    I guess what the OP wanted was an animated variable capacitor with an "UP" and "DOWN" arrow. So he could change the values of the cap on the fly while the circuit is running.

    Using a fixed cap, one can put in a value for the cap, run the simulation. Then stop it and enter a new value for the cap and hit RUN again. That works too.

    Allen
     
    Shayan22h likes this.
  6. Shayan22h

    Thread Starter Member

    Oct 24, 2012
    30
    3
    i don't know much about proteus that is the problem :) i am using multilism it is such a great strong software but the problem the library is not as complete as proteus and it doesnt have the voltage to frequency convertor LM2917, i shall try the spice simulators then, does it have LM2917 ?
    thanks for ur time and help !
    Best Regards,
    shayan
     
  7. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    Shayan22h likes this.
  8. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Why do you want a variable capacitor on pin 5 of the 555 oscillator? The capacitor does not adjust the oscillator frequency, it simply smooths power supply fluctuations.

    R3, R4 and C3 set the frequency of the oscillator. You have the frequency set too high to blink the LED.
     
    Shayan22h likes this.
  9. Shayan22h

    Thread Starter Member

    Oct 24, 2012
    30
    3

    well i am having my semester project which i have a stretchable capacitor sensor so i should convert the capacitance to the frequency and then convert the frequency to the voltage, as i stretch my sensor i am supposed to get different output voltage, well that is the reason i use variable capacitor.
    cheers :)
     
  10. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Then use the variable capacitor at pin 2 and pin 6 (C3 in your circuit) to vary the frequency of the oscillator.
     
    Shayan22h likes this.
  11. Shayan22h

    Thread Starter Member

    Oct 24, 2012
    30
    3
    yeah sure i know that i must use a variable capacitor instead of C3 mate ;) to vary the frequency but my problem is the software proteus offers the variable capacitor but it needs to be configured first which i dont know but it is ok i am gonna use the method suggested by our friend, several capacitors connected to the switch :)
    anyway thanks mate,
    cheers ;)
     
Loading...