Servo motor prob

Discussion in 'General Electronics Chat' started by gusmas, Nov 7, 2009.

  1. gusmas

    Thread Starter Active Member

    Sep 27, 2008
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    0
    Ok nw i am using a tripple 5 timer to position the servo , they both get their supply voltages from the same source, nw when i remove the puls frm the servo it goes back to its default position and i dnt want that, bt ive noticed that if i jst removd the supplie voltage frm the servo and then after 1sec the i remove pulse then the servo stays in that position, so guys i need help, i want to remove the supply frm the servo and 555 at the same time, but i want a kind of delay on the 555 supply after i remove the supply, so fr example, b0th 555 timer and servo they share the same line for Vcc, when i remove the supply the servo mst be off bt the 555 mst still hve a supply fr lets say 0.5sec....
     
  2. gusmas

    Thread Starter Active Member

    Sep 27, 2008
    239
    0
    Ok i gt a solution, just a simple rc cct, wl that work?
     
  3. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    A capacitor decoupled with a diode should do what you want. Feed power directly to servo and anode of diode, couple cathode side of diode to fairly large sized cap and feed 555 from cap. Resistor not needed. Cap size would depend upon current draw of your 555 circuit. Bigger cap = longer delay.
     
  4. gusmas

    Thread Starter Active Member

    Sep 27, 2008
    239
    0
    Ok i see, but the diode wil have a volt drop acros it so ill need to increase the supply?
     
  5. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    The diode will only drop about 0.7 volts. If you need to have matched supply to the servo and the 555, simply put a diode in series with both. The cap across the 555 Vcc-Ground connection will keep the 555 pulsing after the power is disconnected. Again, how long the 555 will keep pulsing will depend upon the size of the cap.
     
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