Lab 23 TF EIM

From New IAC Wiki
Jump to navigation Jump to search

Inverting OP Amp

  1. Construct the inverting amplifier according to the wiring diagram below.
  2. insert a 0.1 μF capacitor between ground and the OP power supply input pin.

Gain measurements

  1. Measure the gain as a function of frequency between 100 Hz and 2 MHz for three values of R_2 = 10 kΩ, 100 kΩ, 1MΩ.
  2. Graph the above measurements with the Gain in units of decibels (dB) and with a logarithmic scale for the frequency axis.

Impedance

Input Impedance

  1. Measure Rin for the 10 fold and 100 fold amplifier at ~100 Hz and 10 kHz frequency.

Output Impedance

  1. Measure Rout for the 10 fold and 100 fold amplifier at ~100 Hz and 10 kHz frequency. Be sure to keep the output (Vout) undistorted

Vio and IB

Vout=R1R2V1+(1+R1R2)Vio+R2IB

Use the above equation and two measurements of Vout, R1, and R2 to extract Vio and IB.

  1. measure Vout for R1 = 1 kΩ, R2 = 100 kΩ, andVin=0 (grounded).
  2. measure [[File:V_{out}]] for R1 = 10 kΩ, R2 = 1 MΩ, andVin=0 (grounded).
  3. You can now construct 2 equations with 2 unknowns Vout and IB.

Iio

Now we will put in a pull up resistor R_3 as shown below.

Instead of the current IB we have the current Iio

Vout=R1R2V1+(1+R1R2)Vio+R2Iio

Use the same technique and resistors from the previous section to construct 2 equations and 2 unknowns and extract Iio, keep Vin=0.

The offset Null Circuit

  1. Construct the offset null circuit below.
  2. Adjust the potentiometer to minimize Vout with Vin=0.
  3. Use a scope to measure the output noise.

Capacitors

Revert back to the pull up resistor

Capacitor in parallel with R2

  1. Select a capacitor such that1ωC2R2 when ω= 10 kHz.
  2. Add the capacitor in parallel to R2 so you have the circuit shown below.
  3. Use a pulse generator to input a sinusoidal voltage Vin
  4. Measure the Gain as a function of the Vin frequency and plot it.

Capacitor in series with R_1

  1. Select a capacitor such that1ωC2R1 when ω= 1 kHz.
  2. Add the capacitor in series to R1 so you have the circuit shown below.
  3. Use a pulse generator to input a sinusoidal voltage Vin
  4. Measure the Gain as a function of the Vin frequency and plot it.


Forest_Electronic_Instrumentation_and_Measurement