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university:courses:electronics:electronics-lab-22 [05 Mar 2019 12:33]
amiclaus [Questions:]
university:courses:electronics:electronics-lab-22 [12 Jul 2019 14:07] (current)
andreeapop
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-====== Activity ​22. Optocouplers. ======+====== ActivityOptocouplers. ======
  
 ===== Objective: ===== ===== Objective: =====
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 In this activity you will construct an optocoupler from an infra-red LED and an NPN photo transistor. You will investigate the operation of an optocoupler based analog isolation amplifier and floating current source using integrated optocouplers. In this activity you will construct an optocoupler from an infra-red LED and an NPN photo transistor. You will investigate the operation of an optocoupler based analog isolation amplifier and floating current source using integrated optocouplers.
  
-===== 22.1 The NPN transistor Optocoupler =====+===== The NPN transistor Optocoupler =====
  
 ==== Background: ==== ==== Background: ====
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 Open the frequency display within the scope window. Adjust the time base such that the fundamental and the first 5 or 6 harmonics are displayed. Write down and save the magnitudes of the fundamental and up to at least the 4<​sup>​th</​sup>​ harmonic for future reference. Open the frequency display within the scope window. Adjust the time base such that the fundamental and the first 5 or 6 harmonics are displayed. Write down and save the magnitudes of the fundamental and up to at least the 4<​sup>​th</​sup>​ harmonic for future reference.
  
-===== 22.2 Driving the LED with a voltage to current converter =====+===== Driving the LED with a voltage to current converter =====
  
 By putting the LED in the feedback loop of an op amp configured as a voltage to current converter we can greatly reduce the effect of the nonlinearity of the LED. By putting the LED in the feedback loop of an op amp configured as a voltage to current converter we can greatly reduce the effect of the nonlinearity of the LED.
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 Compare your distortion measurements for this circuit to what you measured for the previous circuit. How much have the harmonics improved? Compare your distortion measurements for this circuit to what you measured for the previous circuit. How much have the harmonics improved?
  
-===== 22.3 Analog Isolation amplifier. =====+=====  Analog Isolation amplifier. =====
  
 To make a more linear amplifier two matching optocouplers can be used. It is best to use integrated versions for this circuit. To make a more linear amplifier two matching optocouplers can be used. It is best to use integrated versions for this circuit.
university/courses/electronics/electronics-lab-22.txt · Last modified: 12 Jul 2019 14:07 by andreeapop