Lab 3 - EE 420L Engineering Electronics II 

Author: Matthew Meza

Email: mezam11@unlv.nevada.edu

February 6, 2015 

  

Op-Amps I, Basic Topoligies, Finite Gain, and Offset

Click on any picture for its full size!
 
 Pre-lab work
Lab Description
Lab Data
 

For the following questions and experiments assume VCC+ = +5V and VCC- = 0V.

                     Build, and test, the following circuit.
fig1.jpg
 
DC coupled
Offset Voltage
Input and Output
AC Coupled
AC Input and Output
180 degrees out of phase
Clipping when the input
voltage is too high




 
 
Explain how the following circuit can be used to measure the op-amp's offset voltage.

fig2.jpg
The circuit above outputs 2.5 volts. Current flows from Vout to Vm through the 20k resistor while the input bias current
flows from Vm. The input bias current is sometimes small compared to the feedback current, although increasing the RF value
will lower the current that flows from Vout to Vm closer to Vm. This will make the small ofset voltage more noticable as the
current through RF is around the same value as the input bias current.


 
Op-Amp 1 ~ +20mV
Op-Amp 2 ~ -20mV


Op-Amp 3 ~ 0mV
Op-Amp 4 ~ +40mV


 
      

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