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university:courses:electronics:electronics-lab-nr [24 Apr 2017 08:56]
amiclaus rename
university:courses:electronics:electronics-lab-nr [23 Aug 2019 14:06] (current)
amiclaus
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 Open the voltage supply control and the voltmeter instrument windows from the Scopy software. A DMM, if available, could be useful to more accurately measure the DC voltages in the circuit than the Scopy voltmeter instrument. Open the voltage supply control and the voltmeter instrument windows from the Scopy software. A DMM, if available, could be useful to more accurately measure the DC voltages in the circuit than the Scopy voltmeter instrument.
 +{{ :​university:​courses:​electronics:​anr_f2bb.png?​ |}}
 +
 +<WRAP centeralign>​ Figure 3 LED based volt regulator breadboard connections </​WRAP>​
  
 =====Procedure:​===== =====Procedure:​=====
  
 Turn on both the positive and negative power supplies. Observe the two voltages at -V<​sub>​REF</​sub>,​ pins 8 and 14 of the op amp and at +V<​sub>​REF</​sub>​ on the LED. Turn on both the positive and negative power supplies. Observe the two voltages at -V<​sub>​REF</​sub>,​ pins 8 and 14 of the op amp and at +V<​sub>​REF</​sub>​ on the LED.
 +{{ :​university:​courses:​electronics:​anr_f2ss.png?​600 |}}
 +
 +<WRAP centeralign>​ Figure 4 Scopy voltmeter</​WRAP>​
  
 =====Questions:​===== =====Questions:​=====
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 {{ :​university:​courses:​electronics:​anr_f3.png?​600 |}} {{ :​university:​courses:​electronics:​anr_f3.png?​600 |}}
  
-<WRAP centeralign>​ Figure ​3, NPN shunt band-gap reference example </​WRAP>​+<WRAP centeralign>​ Figure ​NPN shunt band-gap reference example </​WRAP>​
  
 =====Hardware setup:===== =====Hardware setup:=====
  
 The setup is the same as step 1. The setup is the same as step 1.
 +{{ :​university:​courses:​electronics:​anr_f6.png?​ |}}
 +
 +<WRAP centeralign>​ Figure 6 LED based volt regulator example </​WRAP>​
  
 =====Procedure:​===== =====Procedure:​=====
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 ====Testing supply headroom==== ====Testing supply headroom====
  
-To test the headroom requirements for +V<​sub>​DD</​sub>,​ disconnect the fixed positive power supply from +V<​sub>​DD</​sub>​ and remove any supply decoupling capacitors. Be sure to turn off the power supplies before making any changes or additions to your breadboard. Now connect +V<​sub>​DD</​sub>​ to AWG 1. Set AWG 1 to trapezium (trapezoid) ​ waveform at 100 Hz. Set the amplitude to 2.5V with a 2.5V offset for a 0 to +5V swing. Connect scope channel 1 to the output of AWG1 and connect scope channel 2 to -V<​sub>​REF</​sub>​ of the first example circuit at pin 14 of the OP482. Use the oscilloscope instrument in the XY mode, scope channel for X and scope channel 2 for Y. Start AWG 1 and turn on the fixed negative 5V  power supply. Record the minimum +V<​sub>​DD</​sub>​ voltage where -V<​sub>​REF</​sub>​ starts to remain constant at -1.25V. +To test the headroom requirements for +V<​sub>​DD</​sub>,​ disconnect the fixed positive power supply from +V<​sub>​DD</​sub>​ and remove any supply decoupling capacitors. Be sure to turn off the power supplies before making any changes or additions to your breadboard. Now connect +V<​sub>​DD</​sub>​ to AWG 1. Set AWG 1 to trapezium (trapezoid) ​ waveform at 100 Hz. Set the amplitude to 5V peak-to-peak ​with a 2.5V offset for a 0 to +5V swing. Connect scope channel 1 to the output of AWG1 and connect scope channel 2 to -V<​sub>​REF</​sub>​ of the first example circuit at pin 14 of the OP482. Use the oscilloscope instrument in the XY mode, scope channel for X and scope channel 2 for Y. Start AWG 1 and turn on the fixed negative 5V  power supply. Record the minimum +V<​sub>​DD</​sub>​ voltage where -V<​sub>​REF</​sub>​ starts to remain constant at -1.25V.
- +
-To test the headroom requirements for -V<​sub>​SS</​sub>,​ reconnect +V<​sub>​DD</​sub>​ to the fixed positive power supply. Disconnect the fixed negative power supply from -V<​sub>​SS</​sub>​ and remove any supply decoupling capacitors. Now connect -V<​sub>​SS</​sub>​ to AWG 1. Set the amplitude to 2.5V with a -2.5V offset for a 0 to -5V swing. Start AWG 1 and turn on the fixed positive 5V  power supply. Repeat your measurements of pins 14 of the OP482 recording the lowest value for -V<​sub>​SS</​sub>​ where the reference voltage is constant. +
- +
-=====Questions:​=====+
  
 +To test the headroom requirements for -V<​sub>​SS</​sub>,​ reconnect +V<​sub>​DD</​sub>​ to the fixed positive power supply. Disconnect the fixed negative power supply from -V<​sub>​SS</​sub>​ and remove any supply decoupling capacitors. Now connect -V<​sub>​SS</​sub>​ to AWG 1. Set the amplitude to 5V peak-to-peak with a -2.5V offset for a 0 to -5V swing. Start AWG 1 and turn on the fixed positive 5V  power supply. Repeat your measurements of pins 14 of the OP482 recording the lowest value for -V<​sub>​SS</​sub>​ where the reference voltage is constant.
  
 =====Directions Step 3:===== =====Directions Step 3:=====
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 {{ :​university:​courses:​electronics:​anr_f4.png?​600 |}} {{ :​university:​courses:​electronics:​anr_f4.png?​600 |}}
  
-<WRAP centeralign>​ Figure ​4, NPN three terminal band-gap reference example </​WRAP>​+<WRAP centeralign>​ Figure ​NPN three terminal band-gap reference example </​WRAP>​
  
 =====Hardware setup:===== =====Hardware setup:=====
  
 The setup is the same as step 1. The setup is the same as step 1.
 +{{ :​university:​courses:​electronics:​anr_f8.png?​ |}}
 +
 +<WRAP centeralign>​ Figure 8 LED based volt regulator example </​WRAP>​
  
 =====Procedure:​===== =====Procedure:​=====
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 Repeat the supply headroom tests you did in Step 2 for this configuration. Are there any differences?​ Repeat the supply headroom tests you did in Step 2 for this configuration. Are there any differences?​
  
 +<WRAP round download>​
 +**Resources:​**
 +  * Fritzing files: [[ https://​minhaskamal.github.io/​DownGit/#/​home?​url=https://​github.com/​analogdevicesinc/​education_tools/​tree/​master/​m2k/​fritzing/​neg_voltage_ref_bb | neg_voltage_ref_bb]]
 +  * LTspice files: [[ https://​minhaskamal.github.io/​DownGit/#/​home?​url=https://​github.com/​analogdevicesinc/​education_tools/​tree/​master/​m2k/​ltspice/​neg_voltage_ref_ltspice | neg_voltage_ref_ltspice]]
 +</​WRAP>​
 ====For further reading:​==== ====For further reading:​====
  
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 ====Appendix:​==== ====Appendix:​====
 +
  
  
university/courses/electronics/electronics-lab-nr.1493016965.txt.gz · Last modified: 24 Apr 2017 08:56 by amiclaus