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university:courses:electronics:electronics-lab-8a [14 Dec 2012 21:29] – [Questions:] Doug Mercer | university:courses:electronics:electronics-lab-8a [20 Jul 2022 20:35] (current) – [Objective:] Doug Mercer | ||
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- | ====== Activity | + | ====== Activity: A Floating (two terminal) Current Source / Sink ====== |
- | ===== Objective: ===== | + | =====Objective: |
The objective of this activity is to investigate the ΔV< | The objective of this activity is to investigate the ΔV< | ||
+ | =====Background: | ||
+ | |||
+ | The [[adi> | ||
+ | |||
+ | The AD590 uses a fundamental property of silicon BJT transistors to realize its temperature proportional characteristic. If two identical transistors are operated at a constant ratio of collector current densities, r, then the difference in their base-emitter voltage is (kT/q)(In r). Because both k (Boltzman’s constant) and q (the charge of an electron) are constant, the resulting voltage is directly proportional to absolute temperature (PTAT). For more details please refer to the datasheet. | ||
===== Materials: ===== | ===== Materials: ===== | ||
- | Analog Discovery Lab hardware\\ | + | ADALM2000 Active Learning Module\\ |
Solder-less breadboard\\ | Solder-less breadboard\\ | ||
1 - 500Ω Variable Resistor, Potentiometer\\ | 1 - 500Ω Variable Resistor, Potentiometer\\ | ||
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===== Directions: ===== | ===== Directions: ===== | ||
- | Build the circuit shown in figure 1 on your solder-less breadboard. The green boxes indicate where to connect the Discovery instruments. PNP transistors Q< | + | Build the circuit shown in figure 1 on your solder-less breadboard. The green boxes indicate where to connect the ADALM2000. PNP transistors Q< |
{{ : | {{ : | ||
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===== Hardware setup: ===== | ===== Hardware setup: ===== | ||
- | Configure waveform generator AWG1 as a triangle wave with a frequency of 100 Hz and an amplitude of 5 V with 0 V offset. The scope display should be set in both voltage vs. time and in XY mode with channel 1 on the horizontal axis and channel 2 on the vertical axis. Be sure to turn on the power supply only after you have completed and double checked your connections. | + | {{: |
+ | |||
+ | <WRAP centeralign> | ||
+ | |||
+ | Configure waveform generator AWG1 as a triangle wave with a frequency of 100 Hz and an amplitude of 10 V peak-to-peak | ||
+ | |||
+ | ===== Procedure: ===== | ||
+ | |||
+ | <WRAP centeralign> | ||
+ | |||
+ | <WRAP centeralign> | ||
===== Questions: ===== | ===== Questions: ===== | ||
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===== Prove the floating nature of circuit: ===== | ===== Prove the floating nature of circuit: ===== | ||
- | In figure 1 we referenced the negative end of the circuit to a negative power supply. To prove that this circuit is truly a floating current source, rearrange your breadboard to look like figure | + | In figure 1 we referenced the negative end of the circuit to a negative power supply. To prove that this circuit is truly a floating current source, rearrange your breadboard to look like figure |
{{ : | {{ : | ||
- | <WRAP centeralign> | + | <WRAP centeralign> |
+ | |||
+ | ===== Hardware setup: ===== | ||
+ | |||
+ | {{: | ||
+ | |||
+ | <WRAP centeralign> | ||
+ | |||
+ | ===== Procedure: ===== | ||
+ | |||
+ | <WRAP centeralign> | ||
+ | |||
+ | <WRAP centeralign> | ||
===== Questions: ===== | ===== Questions: ===== | ||
Is there any measurable difference in the current vs. voltage characteristics for the circuit used as a current sink vs. a current source? | Is there any measurable difference in the current vs. voltage characteristics for the circuit used as a current sink vs. a current source? | ||
+ | |||
+ | <WRAP round download> | ||
+ | **Resources: | ||
+ | * Fritzing files: [[downgit> | ||
+ | * LTspice files: [[downgit> | ||
+ | </ | ||
**Return to Lab Activity [[university: | **Return to Lab Activity [[university: |