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Why are you using that circuit instead of a simple non-inverting opamp circuit?Dextrine said:I am trying to measure the voltage out of this dc-dc converter and am wondering if this method would work.
The ground center point of the op amp bias is not the same reference as the return for the dc-dc output.
Thanks for any help
Dextrine said:I am trying to measure the voltage out of this dc-dc converter and am wondering if this method would work.
The ground center point of the op amp bias is not the same reference as the return for the dc-dc output.
Your arrangement shows the + input of the op-amp being held at a potential partway between that of the two grounds. For the amplifier results to be steady and predictable the potential difference between the two grounds must be fixed, known, and stable.Dextrine said:I am trying to measure the voltage out of this dc-dc converter and am wondering if this method would work.
The ground center point of the op amp bias is not the same reference as the return for the dc-dc output.
If the resistors are correct, the opamp will "calculate" the (voltage proportional to the) exact difference between the input and input's ground. It works like an instrumentation amplifierNascentOxygen said:Your arrangement shows the + input of the op-amp being held at a potential partway between that of the two grounds. For the amplifier results to be steady and predictable the potential difference between the two grounds must be fixed, known, and stable.
Have you established what the resistance relation must be in order for this to be true?AlexCaledin said:If the resistors are correct, the opamp will "calculate" the (voltage proportional to the) exact difference between the input and input's ground. It works like an instrumentation amplifier
https://en.wikipedia.org/wiki/Instrumentation_amplifier
Why, the only basic requirement is obvious: If the measured input is at the signal-ground potential (that is, the measured voltage is zero), then the resistors connected to the negative input of the op-amp must make there, when the output is zero, exactly the same potential as that of the positive input ― whatever the signal-ground potential is.NascentOxygen said:Have you established what the resistance relation must be in order for this to be true?
That is the theoretical requirement. You also need to ensure that the op-amp inputs are within the active range and that the op-amp output is within the specified range.AlexCaledin said:Why, the only basic requirement is obvious: If the measured input is at the signal-ground potential (that is, the measured voltage is zero), then the resistors connected to the negative input of the op-amp must make there, when the output is zero, exactly the same potential as that of the positive input ― whatever the signal-ground potential is.
― oh yes I need, but that's not necessarily change the resistors (― and the question was about resistors' relation ) ― I can, in principle, increase those ranges choosing/building a high-voltage opamp.Svein said:That is the theoretical requirement. You also need to ensure that the op-amp inputs are within the active range and that the op-amp output is within the specified range.
An Opamp, short for operational amplifier, is an electronic device used in analog circuits to amplify and manipulate signals. It has two inputs, an inverting and a non-inverting input, and one output. The output voltage is the difference between the two input voltages multiplied by a gain factor. It is typically used to amplify weak signals, perform mathematical operations, and act as a voltage comparator.
No, an Opamp has specific input and output configurations that must be followed in order for it to function properly. The most common configuration is the inverting or non-inverting amplifier, where one input is grounded and the other is connected to the input signal. Other configurations include the differential amplifier, integrator, and differentiator.
If the power supply is not connected correctly, the Opamp will not function properly. The power supply provides the necessary voltage for the Opamp to amplify the signal. If it is not connected or connected incorrectly, the Opamp may output incorrect or no signal at all.
Yes, an Opamp can work with both AC and DC signals. However, the Opamp's frequency response and gain may be limited, and additional circuitry may be needed to properly amplify AC signals. In general, Opamps are better suited for amplifying DC signals.
When choosing an Opamp for a specific circuit, some important factors to consider include the required gain, input and output voltage ranges, bandwidth, stability, and power consumption. It is also important to check the Opamp's datasheet for specifications such as input offset voltage, input bias current, and slew rate to ensure it will meet the requirements of the circuit.