Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [source]

Voltage and Frequency are typical absolute sources or references to drive other circuits. You have voltage references and frequency references. Current is defined by placing a known stable voltage across a known stable resistor. Frequency and Time measurements are often driven by a master oscillator such as a XTAL. Precision is defined by the accuracy of your reference sources, which determines how accurate your DVM/LCR/Frequency counter/O-scope are.

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Is current source also a voltage source?

I'm confused between current and voltage sources; I get the text book definition but I am not able to understand real world difference. To me both current and voltage sources seem as the same. I understand that ideal sources doesn't exist. What is…
user3551094
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*Very* high precision, *very* stable current source

My background: experimental physics. Not an electrical engineer, but I have some experience putting together basic electronic circuits for physics experiments. So please be kind and explain as if I'm a noob. Thank you! What I'm trying to do: A very…
ugachmaaz
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Constant current source design considerations

I am designing a constant current source to drive a laser diode. I need it to be adjustable (from 0 to 100mA max) and stable enough as I will be using it as a light source in a Foucault mirror tester for my amateur telescope mirror making…
nonius
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Are these 2 resistors in parallel?

So I had a circuit to analyse and I needed to find the equivalent resistor and then I arrived to a confusion. Are R1 and R3 in parallel? Here is the circuit. simulate this circuit – Schematic created using CircuitLab
P_M
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Purpose of these two transistors

Hi does anybody know what's the purpose of the Q1 and Q2 transistors, sounds to me like they are constant current sources. Am I wrong? Could somebody explain me the purpose of those Q1 and Q2 transistor configuration there? Note, This is a simple…
Standard Sandun
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Why does current have to return to its source in a circuit?

As far as I know there should be a current when a high potential point is connected to a low potential point, but apparently that is not true. I understand that a circuit must be closed in order for it to flow. I just don't get why a return path to…
poh
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Can a current source have a voltage across it?

I'm reviewing material from a lower div circuits class in preparation for the upper div class by redoing problems, and this is one of them. Does it make sense for the branch with the dependent current source to have a voltage Va(t) across it?…
jonnyd42
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Capacitor discharge and 1/2 terminal voltage sources

I understand that this is really basics of electronics, but I would really appreciate if somebody clearly explained following question. So here is a small set of questions related to similar topic: What's the difference between 1 and 2 terminal…
Arturs Vancans
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Connecting Switches to Hidden Supply Pins in Proteus ISIS

I am currently working on a simple circuit involving logic gates in Proteus ISIS from Labcenter. By default, the power pins are hidden. You can access them by right-clicking the component, selecting "Edit properties", and going to "Hidden pins". You…
DerStrom8
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Alternate between 0 and 180° shift at regular intervals for a sine source during a .tran operation on LTspice

Is it possible to alternate between a 0 and 180° shift at regular intervals (say every second) for a sine source in a circuit during a .tran operation in LTspice? (I need to see the reaction of my circuit to a phase shift) I am using LTspice XVII
c.leblanc
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Proving that this JFET + Bipolar source follower give back a linear output

I was reading about this source follower and wondered how the bipolar transistor makes Vgs somewhat stable. I believe that what happens here is that when Vin is high more current flows through the base of the bipolar and then more voltage drops…
The pro coder not really xd
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Driving Relay Board with Shift Register (Shift vs Sink)

I am trying to drive some ebay bought 8 channel relay boards. They are pretty simple, have a launchpad or arduino toggle a pin and the board turns on. However, I need to use a shift register with them. I have absolutely no idea how to think about…
Dan
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Understanding a transistor configuration

I started watching this video series on a DIY lab power supply by Dave @ EEVBlog. On his video he's analyzing mostly simple constant current circuit. However, at the top of the circuit there's two transistors in the op-amp feedback. He explains…
Paul
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Logic gate using current source and diodes

This circuit is supposed to work as a logic gate. I need to find out the logic operation it performs. Suppose the diodes are ideal. https://www.circuitlab.com/circuit/egg3wh/logicgate/ simulate this circuit – Schematic created using CircuitLab Now…
Douglas Edward
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Open-loop simulation of a voltage-controlled current source

Short summary: V3 decides the current going through R2. If V3 is 0 V then no current is going through R2. If V3 is 10 V, it will be approximately 50 mA. I want to do an open-loop simulation of this voltage-controlled current source. The…
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