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university:courses:electronics:electronics-lab-9 [23 Mar 2017 16:14]
Doug Mercer [Materials:]
university:courses:electronics:electronics-lab-9 [03 Jan 2021 22:21] (current)
Robin Getz fix links
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-====== Activity ​9.  ​Regulated Voltage Reference ======+====== Activity ​Regulated Voltage Reference ======
  
 ====== Version 1 ====== ====== Version 1 ======
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 ===== Objective: ===== ===== Objective: =====
  
-The zero gain amplifier (Q<​sub>​1</​sub>,​ R<​sub>​2</​sub>​) and stabilized current source (Q<​sub>​2</​sub>,​ R<​sub>​3</​sub>​) from activities ​and can be used in conjunction with a PNP current mirror stage (Q<​sub>​3</​sub>,​Q<​sub>​4</​sub>​) in negative feedback to build a circuit which provides a constant or regulated output voltage over a range of input voltages.+The zero gain amplifier (Q<​sub>​1</​sub>,​ R<​sub>​2</​sub>​) and stabilized current source (Q<​sub>​2</​sub>,​ R<​sub>​3</​sub>​) from activities ​10 and 11 can be used in conjunction with a PNP current mirror stage (Q<​sub>​3</​sub>,​Q<​sub>​4</​sub>​) in negative feedback to build a circuit which provides a constant or regulated output voltage over a range of input voltages.
  
 ===== Materials: ===== ===== Materials: =====
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 ===== Hardware Setup: ===== ===== Hardware Setup: =====
  
-Waveform generator 1 should be configured for a 1 KHz triangle wave with volt amplitude and 2V offset. The Single ended input of scope channel 2 (2+) is used to measure the stabilized output voltage at the collector of Q<​sub>​4</​sub>​.+{{:​university:​courses:​electronics:​regulator_v1-bb.png|}} 
 + 
 +<WRAP centeralign>​ Figure 2 Regulator Version 1 Breadboard Circuit </​WRAP>​ 
 + 
 +Waveform generator 1 should be configured for a 1 KHz triangle wave with volt amplitude ​peak-to-peak ​and 2V offset. The Single ended input of scope channel 2 (2+) is used to measure the stabilized output voltage at the collector of Q<​sub>​4</​sub> ​( negative inputs 1= and 2- should be connected to ground).
  
 ===== Procedure: ===== ===== Procedure: =====
  
 Plot the output voltage (as measured at the collector of Q<​sub>​4</​sub>​) vs. the input voltage. At what input voltage level does the output voltage stop changing i.e. regulate? This is called the "drop out" voltage. For input voltages above the drop out voltage, how much does the output voltage change for each volt of change at the input? The change in Vout / change in Vin is called line regulation. Connect a variable resistor from the output node to ground. With the input voltage fixed (i.e. connected to the fixed Vp board power supply), measure the output voltage for various settings of the resistor. Calculate the current in the resistor for each setting. How does the output voltage vary vs. output current? This is called load regulation. Plot the output voltage (as measured at the collector of Q<​sub>​4</​sub>​) vs. the input voltage. At what input voltage level does the output voltage stop changing i.e. regulate? This is called the "drop out" voltage. For input voltages above the drop out voltage, how much does the output voltage change for each volt of change at the input? The change in Vout / change in Vin is called line regulation. Connect a variable resistor from the output node to ground. With the input voltage fixed (i.e. connected to the fixed Vp board power supply), measure the output voltage for various settings of the resistor. Calculate the current in the resistor for each setting. How does the output voltage vary vs. output current? This is called load regulation.
 +
 +<WRAP centeralign>​{{:​university:​courses:​electronics:​regulator_v1-wav.png?​500|}}</​WRAP>​
 +
 +<WRAP centeralign>​ Figure 3 Regulator Version 1 Waveform </​WRAP>​
  
 ====== Version 2: ====== ====== Version 2: ======
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 {{ :​university:​courses:​electronics:​a9_f2.png?​500 |}} {{ :​university:​courses:​electronics:​a9_f2.png?​500 |}}
  
-<WRAP centeralign>​ Figure ​Regulator Version 2 </​WRAP>​+<WRAP centeralign>​ Figure ​Regulator Version 2 </​WRAP>​
  
 ===== Hardware Setup: ===== ===== Hardware Setup: =====
  
-Waveform generator W1 should be configured for a 1 KHz triangle wave with volt amplitude and 2V offset. Scope channel 2 (2+) is used to measure the stabilized output voltage at the emitter of Q<​sub>​4</​sub>​.+{{:​university:​courses:​electronics:​regulator_v2-bb.png|}} 
 + 
 +<WRAP centeralign>​ Figure 5 Regulator Version 2 Breadboard Circuit</​WRAP>​ 
 + 
 +Waveform generator W1 should be configured for a 1 KHz triangle wave with volt amplitude ​peak-to-peak ​and 2V offset. Scope channel 2 (2+) is used to measure the stabilized output voltage at the emitter of Q<​sub>​4</​sub>​.
  
 ===== Procedure: ===== ===== Procedure: =====
  
 Repeat the drop out voltage, line and load regulation measurements for this circuit. How are they different than the first regulator circuit? Repeat the drop out voltage, line and load regulation measurements for this circuit. How are they different than the first regulator circuit?
 +
 +<WRAP centeralign>​{{:​university:​courses:​electronics:​regulator_v2-wav.png?​500|}}</​WRAP>​
 +
 +<WRAP centeralign>​ Figure 6 Regulator Version 2 Waveform </​WRAP>​
  
 ==== For Further Study: ==== ==== For Further Study: ====
  
-ADI Mini Tutorial on [[http://​www.analog.com/​static/​imported-files/​tutorials/​MT-087.pdf|Voltage references]]+ADI Mini Tutorial on [[adi>static/​imported-files/​tutorials/​MT-087.pdf|Voltage references]]
  
 ====== Using an NPN transistor array: ====== ====== Using an NPN transistor array: ======
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 All the emitters can be tired to ground ( pins 3,7,10,13 ). Devices Q<​sub>​1</​sub>,​ Q<​sub>​2</​sub>​ and Q<​sub>​3</​sub>​ can be connected in parallel and serve as Q<​sub>​2</​sub>​ in figure 2. Q<​sub>​4</​sub>​ and Q<​sub>​5</​sub>​can be used for Q<​sub>​1</​sub>​ and Q<​sub>​3</​sub>​in figure 2. An individual device such as a 2N3904 etc. can be used for Q<​sub>​4</​sub>​ in figure 2. The 3 to 1 emitter area ratio will result in an output voltage very nearly 1.2 volts if R<​sub>​1</​sub>​ and R<​sub>​3</​sub>​ are both equal to 2KΩ (when R<​sub>​2</​sub>​ is 100Ω). All the emitters can be tired to ground ( pins 3,7,10,13 ). Devices Q<​sub>​1</​sub>,​ Q<​sub>​2</​sub>​ and Q<​sub>​3</​sub>​ can be connected in parallel and serve as Q<​sub>​2</​sub>​ in figure 2. Q<​sub>​4</​sub>​ and Q<​sub>​5</​sub>​can be used for Q<​sub>​1</​sub>​ and Q<​sub>​3</​sub>​in figure 2. An individual device such as a 2N3904 etc. can be used for Q<​sub>​4</​sub>​ in figure 2. The 3 to 1 emitter area ratio will result in an output voltage very nearly 1.2 volts if R<​sub>​1</​sub>​ and R<​sub>​3</​sub>​ are both equal to 2KΩ (when R<​sub>​2</​sub>​ is 100Ω).
 +
 +<WRAP round download>​
 +**Resources:​**
 +  * Fritzing files: [[downgit>​education_tools/​tree/​master/​m2k/​fritzing/​regulated_voltage_reference_bb | regulated_voltage_reference_bb]]
 +  * LTspice files: [[downgit>​education_tools/​tree/​master/​m2k/​ltspice/​regulated_voltage_reference_ltspice | regulated_voltage_reference_ltspice]]
 +</​WRAP>​
  
 **Return to Lab Activity [[university:​courses:​electronics:​labs|Table of Contents]]** **Return to Lab Activity [[university:​courses:​electronics:​labs|Table of Contents]]**
  
university/courses/electronics/electronics-lab-9.1490282052.txt.gz · Last modified: 23 Mar 2017 16:14 by Doug Mercer