control two circuits in one

Discussion in 'General Electronics Chat' started by Xufyan, Sep 2, 2011.

  1. Xufyan

    Thread Starter Member

    Aug 3, 2010
    114
    0
    I have question regarding using two different opamp circuits as one,

    please have a look at the attachment,

    I want this circuit to work as integrator as well as a differential amplifier using two switches,
    one switch for integrator and the other for Differential,
    when I press 'Integrator' switch, the capacitor C2 must be shorted and Resistor R4 must be opened so the circuit acts like Integrator , when i Press switch for Differential, C1 and R3 must be opened so the circuit become complete differential amplifier.....
    i need some idea on how to open / short these components through a switch, is it possible using digital logics ?? ? Howw ?

    please give me some idea.

    Thank you
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    R4 is really redundant; you need 10k from the output to the inverting input in either case.

    Have a look at the attached. I've removed R4, and used a CD4066 quad analog switch with a SPDT toggle switch and an NPN transistor as an inverter to control the analog switch inputs. The CD4066 adds some error to the circuit, as it has a nominal 150 Ohm resistance from input to output per channel when the "internal switch" is closed.
     
  3. Xufyan

    Thread Starter Member

    Aug 3, 2010
    114
    0
    i am not very good in electronics :/ please provide some simple idea :S i have studied opamp , dld, basics of transistor so far so far
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    I'm sorry the last schematic was difficult to understand.

    I changed it to just use a single DPDT (double-pole double-throw) switch instead.

    The dashed line between S1a and S1b means that they both switch at the same time.
     
    BershaM likes this.
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