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Is there a way to measure the equivalent capacitance from a node to ground in a circuit?

BaaB

Is there a way to measure the equivalent capacitance from a node to ground in a circuit?

I see that the node to ground in captab only reports the capacitance value of an actual capacitor (if exists) from that node to ground not the equivalent capacitance.

Thank you.

Parents
  • BaaB

    Thank you very much for the detailed answer.
    You are right that I chose detail=nodetoground.
    However, I see that the other options (node or nodetonode) also don't return the
    effective capacitance to ground as in the example below.
    I have not simulated it yet but from how capacitance is calculated in each case I don't think the result is right.
    The circuit below includes a bjt transistor and a Miller capacitor between
    base and collector.

    Here is the link to the circuit image: http://postimg.org/image/xvekod2wh/

    (I tried both Chrome and Firefox but both didn't work now).

    I would like to measure the effective capacitance from node A to ground.
    What I expect is (A+1)*C where A is the gain of the inverting amplifier.
    However, the results that simulator returns will be something as below.
    (assuming that the transistor is ideal and there are no parasitic capacitors in the transistor)
    1. detail = nodetoground
    A : 0 - result: 0
    2. detail = node
    A : A - result: C
    3. detail=nodetonode
    A : 0 -result: 0
    A : collector - result: C

Reply
  • BaaB

    Thank you very much for the detailed answer.
    You are right that I chose detail=nodetoground.
    However, I see that the other options (node or nodetonode) also don't return the
    effective capacitance to ground as in the example below.
    I have not simulated it yet but from how capacitance is calculated in each case I don't think the result is right.
    The circuit below includes a bjt transistor and a Miller capacitor between
    base and collector.

    Here is the link to the circuit image: http://postimg.org/image/xvekod2wh/

    (I tried both Chrome and Firefox but both didn't work now).

    I would like to measure the effective capacitance from node A to ground.
    What I expect is (A+1)*C where A is the gain of the inverting amplifier.
    However, the results that simulator returns will be something as below.
    (assuming that the transistor is ideal and there are no parasitic capacitors in the transistor)
    1. detail = nodetoground
    A : 0 - result: 0
    2. detail = node
    A : A - result: C
    3. detail=nodetonode
    A : 0 -result: 0
    A : collector - result: C

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