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How to choose resistor value for op amp?
Resistor values should stay within the range of 1–100 kΩ. The lower limit avoids excessive current draw from the op amp output, which is particularly important for single-supply op amps in power-sensitive applications. Those amplifiers have typical output currents of between 1 mA and 5 mA.
What will be the value of RF and R1 in ohms for an inverting opamp with gain 10?
The gain of an inverting op-amp amplifier is given as -Rf/R1. However, there can be many possible configurations depending on these resistor values, all providing the same gain. For eg: a) Rf=100M, R1=10M b) Rf=100K, R1=10K c) Rf=100, R1=10. All gives gain=10.
How to sense current in a circuit?
The most common way to measure current is to sense the voltage drop across a shunt or current-sense resistor. To achieve a highly accurate measurement of the current, you’ll need to examine the parametric values of both the resistor and current-sense amplifier.
Why are resistor values in op-amps important?
The op-amp is inverting hence the inverting input is at 0 volts hence the output load IS the feedback resistor and you can’t have this too low or you won’t get the output voltage amplitude. On the other hand, you can’t go too big because the parasitic capacitances of the op-amp will start to reduce gain too much at higher frequencies.
How does a current sense resistor circuit work?
The above current sense resistor circuit shows how a shunt resistor is placed in a current carrying path and how the voltage drop across the resistor can be calculated by using a Current Sense Amplifier. You can know more about how current sense amplifiers work for following the linked article.
How is the value of a shunt resistor determined?
Because the value will determine how much voltage will drop during the flow of current. The value can be determined from the current sense amplifier perspective. Depending on the maximum current flow and the maximum input voltage of the current sense amplifier, the value of the shunt resistor can be chosen.
Why do you need a small resistor in an amplifier?
These usually deal with the non-ideal behavior of components (namely Op-Amps), or other design requirements such as power and heat. Small resistors means that you need a much higher current to provide the appropriate voltage drops for the Op-amp to work.