Op-amp resister circuit analysis

In summary, the conversation discusses how to determine the resistor R2 and current I2 in a circuit with an ideal op-amp, given specific values for Vin, Vout, and R1. The equations used include Ohm's law and the voltage divider equation. The solution involves setting V+ and V- equal in the op-amp and using the general closed-loop non-inverting gain formula to find the values for R2 and I2. The final values obtained are R2 = 1,250Ω and I2 = 0.4mA.
  • #1
joel amos
104
0

Homework Statement


Given the ideal op-amp, determine the resistor R2 and the current I2 where Vin=500mV, Vout = 2.5 V, and R1=5kV.
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Homework Equations


No current passes through op-amps, the op-amp tries to make V+ and V- equal.
Ohm's law, voltage divider equation

The Attempt at a Solution


Since V+ is 500mV, I assumed that the node between R1 and R2 must also be 500mV, as it is connected to V-. So 500mV = 2.5V(R2/(5000Ω+R2)). I got R2 to be 1,250Ω.
Then I found I2=Vout/Req = 2.5V/(1250Ω + 5000Ω) = .4mA.
However, I am unsure because I am not sure if I did the part with the op-amp right; namely, the node between the resistors being set to 500mV.
 
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  • #2
You are 100% correct sir.

V+ = V- in ideal opamps...

Nice job.
 
  • #3
Yes - and for the future you can use the general closed-loop non-inverting gain formula (assuming an ideal opamp): Acl=1+R1/R2.
 

1. What is an op-amp resistor circuit?

An op-amp resistor circuit is a type of electronic circuit that uses operational amplifiers (op-amps) and resistors to amplify and manipulate electrical signals. Op-amps are integrated circuits that have high gain and can be used to perform various mathematical operations on input signals.

2. How does an op-amp resistor circuit work?

The op-amp in the circuit compares the input signal with a reference voltage and amplifies the difference between the two. The output of the op-amp is then fed back to the input through a resistor network, which provides the necessary feedback to control the gain and output signal. This feedback mechanism allows the circuit to perform various functions such as amplification, filtering, and integration.

3. What are the key components of an op-amp resistor circuit?

The key components of an op-amp resistor circuit include the operational amplifier, resistors, and power supply. The op-amp is the main component that performs the signal processing, while the resistors are used to control the gain and provide feedback. The power supply provides the necessary voltage for the circuit to function.

4. What are the applications of op-amp resistor circuits?

Op-amp resistor circuits are widely used in electronic devices and equipment, including audio amplifiers, signal filters, analog-to-digital converters, and many more. They are also used in various scientific and industrial applications, such as instrumentation, control systems, and sensors.

5. How do you analyze an op-amp resistor circuit?

To analyze an op-amp resistor circuit, you can use mathematical equations and principles such as Kirchhoff's laws and Ohm's law. You can also use circuit simulation software to model and analyze the circuit's behavior. Additionally, understanding the op-amp's characteristics and the resistor network's configuration is essential for proper analysis.

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