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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4answers
106 views

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 ...
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3answers
75 views

Should I connect the computer VBUS line to the 5V line of the board?

I am doing a project that needs USB communication with my microcontroller. On the board there is already a 5V power supply. I would like to know if it is correct to ...
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89 views

Voltage spreading to resistors network

I want to model several electrodes (say 3) and GND on a resistive substrate. simulate this circuit – Schematic created using CircuitLab To characterise it, I apply a current on one electrode ...
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2answers
49 views

In a thin-film transistor (on insulating substrate) what is the difference between putting a load on the source or drain side of the transistor?

My question was incorrectly posed, because I didn't include the capacitor connecting the gate to one of the terminal. So in fact this question is regarding common source vs common drain comparison...
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2answers
152 views

Variable Current Source

simulate this circuit – Schematic created using CircuitLab I need to build a variable current source that operates off a 36V supply, if possible using a single op-amp and a mosfet. I need to ...
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1answer
51 views

Voltage controlled current source doesn't have constant current

simulate this circuit – Schematic created using CircuitLab I have this circuit for a voltage controlled current source, but it isn't working.The transistor is a Darlington.The circuit is ...
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33 views

High power source and low power load (device) [duplicate]

Can we drive low power load on high power source? For example we have source power 12 volt 60 amp and load power 12 volt 5 amp. Do we need resistor between them? If needed, what value will it be and ...
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20 views

Use of parametric file name in PWL sources

I would like to use a parametric file name for a PWL voltage source inside a subcircuit, so I can use different filenames directly from the symbol on the "top" circuit. I tried the plain PWL file={...
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1answer
48 views

Current source for high current LED driver- 24Vdc/max:16A

I am working on designing a current source for a LED driver, which can work up to max:16A, as long as stays On less than 500msec. Actually, the leds circutry is a Dome-light which is divided in 4 ...
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1answer
82 views

Power Source Symbol — Which to use (Arrow, Bar, Circle, etc.)?

I'm wondering if there is anyone out there with a definitive answer to why and/or what standard would call out the usage of the different voltage sources. There are Bars, Arrows, Dots, Waves, etc. I ...
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2answers
66 views

I'm working on a school Lab for a Constant Current source BJT and need a nudge in the right direction

I am stuck trying to determine the applicable formula for the load current. I have used \$I_b = \frac{Vin-Vbe}{(Beta+1)*Re}\$ and then \$I_L= (Beta)*I_b \$. The problem is I can't find a proper ...
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1answer
38 views

Current mode operation of a Source Measurement Unit (SMU)

I'm studying semiconductor parameter analyzers. In particular, I have difficulties in fully understanding the circuit in the following slide, which represents an SMU operating in I-mode (i.e., it ...
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1answer
101 views

Ultra Stable Current Source At Up To 2 A [closed]

Can anyone suggest circuit(s) that can produce a very stable current source, preferably trimmable to close to 1 or 2 amps? Stability is the main requirement, all help is greatly appreciated. I have ...
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0answers
40 views

Reducing the offset voltage of a source follower

I am currently trying to reduce the offset voltage of the circuit attached below to less than +/- 2mV over a 1V to 4V input range. I have a few constraints for this task: I can use ...
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4answers
289 views

Opamp output to source and to sink

The output impedance of an ideal opamp is zero. The output of an ideal opamp acts as an ideal voltage source. The output of the opamp should be able to output very large currents (to source) and (to ...
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1answer
19 views

common source pole calculation vs. simulation

I would like to compare my pole simulation results to my hand calculations, I'm receiving quite a big error. when simulating a Common Source stage without output capacitance load there is a big ...
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2answers
51 views

Switches for current source

simulate this circuit – Schematic created using CircuitLab I1 is an wilson modified current source by 4 pnp transistors. SW1 and SW2 are doubts. When SW1 is open, SW2 must be closed and vice ...
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0answers
35 views

Current source output

What can I do to eliminate the output voltage when there is no load on my circuit, even if there is any level on V2? I have do develop a current source that doesn't provide output when no load. Thanks
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34 views

Current Source Output Stage

I'm developing a current source based on NPN Wilson modified current mirror. There's a restriction that cannot be used opamps, so i'm using only transistors. However, it's fundamental that doesn't ...
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0answers
50 views

A source generator connected to a receiver with a lossy transmission line

Consider that we have a 50-ohm source generator that is connected to a 300 ohm transmission line. This line has a loss of 10 dB for every 100 ft and is connected to a 50 ohm receiver. The source ...
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1answer
64 views

MASTER Clock output from one micro to another vs independent clock src

I have a Small STM32 Nucleo board where the on-board ST-Link debugger has an 8mhz crystal for the debugging microcontroller. That microcontroller is set up to output its MASTER clock, in other words ...
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1answer
57 views

Voltage Controlled Voltage Source Circuit Analysis

I don't know what I'm missing with the analysis of this question. Obviously I know that there's no voltage through the 105k resistor. I know that the current from the VCCS is given by the input ...
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1answer
65 views

Ringing at mosfet source just before turning on

I am working on buck converter but stuck on at the basic results. I simulated my circuit in OrCad. Attaching my circuit diagram and waveforms. The problem is with the voltage at source of mosfet....
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1answer
102 views

Adjustable voltage source 10 – 50 V and adjustable current limiter 2 – 70 mA

I would like to build a source that gives on the output an adjustable voltage from 10 V to 50 V and that current be limited from 2 mA to 70 mA or make some circuit that let me choose 2 mA, 1 0mA, 50 ...
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1answer
47 views

Analysis of 3 Stage CS Ring Oscillator

I am new to the world of oscillators, so take it easy on me. I have been attempting to analyze the following common source ring oscillator: However, I am having some trouble here. So based on my ...
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2answers
138 views

Wiring of body terminal in a network of MOSFET switches

I am trying to design a set of switches in a cmos design. The switches are supposed to control a number of capacitors and I want to implement them as single NMOS or PMOS transistors. Based on my ...
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1answer
75 views

Source Transformation

Ok, I have modified my question again about the same circuit seen below: I have to simplify the circuit using source transformation and then find the current ix. I have attached my attempted ...
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2answers
107 views

Combining two ideal voltage sources with an impedance between them

Solving a problem, I came across the following source transformation:        My question is: I know that I can do the following:       &...
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1answer
232 views

Can a Dependent source be dependent on itself?

I am looking for the Thevenin Resistance here. However, I have no clue what to do with \$i_b\$ and the source dependent on it. This is the entire circuit. \$i_b\$ is the current through the 5\$k\...
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1answer
64 views

Single tone signal generation at microwave frequency with best phase noise and spurious performance

What is the best way to generate a single tone signal with best phase noise and spurious performance? Is frequency multiplication the best way? single stage multiplication or multi stage ...
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1answer
174 views

Confusion with signal/source being low or high impedance [closed]

Regarding the following excerpt: High impedance source gives you more volts and less current Low impedance source gives you lower voltage but more current What ...
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3answers
542 views

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 ...
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2answers
355 views

Opamp current source stable in simulation but unstable on prototype

I've tried to build this opamp/mosfet current source, and been struggling to make it stable. When simulating the open-loop gain in PSpice. I've set it up like this, which should give Vout = -AB at the ...
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1answer
523 views

op amp current source oscillating

I know this topic has been discussed a lot, but there seems to be varying opinions about the solutions.. The problem is we are trying to make a current source with an op-amp driving a FET as the load....
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0answers
416 views

Design a Voltage controlled current source

I have to create a current source (cs) capable of delivering up to 1.5 amps in order to calibrate a IC. The cs must be adjustable through a signal generator. I thought I could use an op-amp and I ...
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3answers
209 views

Implementing a constant current source circut that can be switched off by a voltage signal

Does anyone know how to implement a constant current source circuit that is able to output 10mA constantly, ideally the load of the circuit would be a 100uF capacitor in series with 100 Ohms. Is ...
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1answer
92 views

Based on what should i choose an amplifier to implement a Howland current pump with?

I selected some amplifiers based on their input and output voltage since the howlands Gain is Vin/R also on how much current the amplifier can supply. i selected ones that are 100mA and up, what other ...
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0answers
58 views

resistor at external clock source line [duplicate]

im reading a arm based mcu board schematic and there is 100R resistor (R30) at external 25MHz oscillator source. What is the main reason of using serial resistor at clock line ?
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2answers
46 views

What would be the best way to power 10 AAA powered torches with mains power (240v)

We manufacture small AAA powered RGB torches. To test them I'd like to power up 10 at a time with crocodile clips. Ideally, the power source would be a mains powered supply. Would wiring off a multi-...
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2answers
62 views

Researching chips and sourcing components [closed]

How do you research and select a chip for a given task? Are there some formalised and centralised databases I should be using? This would go equally for pre-assembled modules. Following on, where ...
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2answers
82 views

Interactions between Ideal Voltage and Current Sources

Last week I asked a question involving a linear network involving ideal current and voltage sources. You guys gave me some great advice as to how to approach those types of problems. However, this ...
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2answers
140 views

Ideal Voltage/Current Source Circuit Analysis

I am trying to understand what it going on in this circuit diagram and how to go about solving this problem. I am told to find Vx given that the current in the central wire is zero. Does this mean ...
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2answers
507 views

How to make a symmetrical DC power source?

I have been tasked with creating a logic probe that reads High/Low/High Impedance, but what works in simulations, isn't working in practice. This was my idea: I made a symmetrical power source using ...
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4answers
2k views

Thevenin equivalent, of circuit with one voltage and one current source

I am a Computer Engineering Student, and we have a lesson called Electric Circuits. I am trying to understand Thevenin's Theorem, but there is a circuit that confused me. simulate this circuit –...
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2answers
87 views

Why do some electric circuts need 2 or more voltage sources [closed]

Why would we put 2 voltage sources(bateries) into an electric circut ? What are some real world examples where they are needed ?
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1answer
309 views

Voltage source and its load resistance matching

i have implemented DAC controlled DC voltage source. I'm having trouble understanding physical reasons for voltage error due to load resistance change. My circuit desing was taken from DAC ...
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1answer
64 views

How is this source actually connected in the circuit?

I have seen this way of connecting the source in a couple of books now but I still am not sure if I am getting it right. This is how I am interpreting it, I have a feeling I'm very much wrong. The ...
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7answers
5k views

*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 ...
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1answer
377 views

Can I use a power supply as a constant current source?(+general understating problems)

I beg you pardon if the question sounds trivial. I have a Power Supply that can provide a outer voltage between 0 and 32 V , and an outer current between 0 and 10 A. I would like to connect a ...
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1answer
934 views

How can a grounded gate MOSFET conduct current?

I am trying to get into understanding of current mirrors, amplifiers and other basic electronic blocks, and I have come across this a lot, but I couldn't find an explanation how that works anywhere (...