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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47 views

Current source with variable frequency

My application requires a current source with variable frequency. The amplitude of current will be around 10nA. The frequency of current to be more than 100Hz. I'll be highly obliged if someone helps ...
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22 views

Parameters of two port networks

Is parameters(Z parameter, Y parameter etc.) of two port networks are constants? I try to figure out this and found that if network contain some active elements or independent source then these ...
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60 views

Adjustable current source 0-20mA for LED dimming

I have been searching through the site, but I have not been able find an answer. I have an LED (rated for 14 mA at 24V, the LED is with built-in series resistor) that I need to be able to dim from ...
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103 views

Current source schematics. What's the difference?

I have two current source schematics. They are nearly identical and one could be transformed to another by moving componets and voltage sources around. Both are set to 1 mA output. But the left one ...
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82 views

Confusion with non-ideal current and voltage source models

I have a confusion with the following explanation of non-ideal voltage and current sources: These above doesn't look like the Thevenin or Norton models since the plots are non linear. Can someone ...
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3answers
53 views

Impedance Matching between Source and Load

I am having this basic doubt In the basic crude basic block diagram, we have a source, transmission line and load, all having an impedance of 50Ohms. But according to maximum power transfer theorem, ...
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66 views

Calculate MOSFET Forward Voltage Drop

I'd like to better understand how to calculate the voltage drop between the Drain and the Source of a FET. As an example, say we have a MDD1902 N-channel FET. How would I determine the maximum ...
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77 views

What could happen if I touch a constant current source for example 5 Volts 1 Amp..?

Yes, I am talking about a constant current source not a voltage source. Would the 1 Amp go to my body?
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101 views

How do I know if a current source supplies or receive energy?

In example, I have this circuit: I know that in a current source if the polarty is \$-\rightarrow +\$ it supplies energy to the circuit, but how I can determinate the polarity in this case (of \$I_{...
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21 views

Voltage Noise Simulation with white noise variation issue

I am trying to simulate the behaviour differential AOP, with its input common mode and differential mode filters, which is placed at the 2 outputs of the sensor, whose one is noisy. Of course, the ...
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66 views

ATtiny13 at 16MHz? Why not?

How exactly are you supposed to run the ATtiny13 at 16MHz or higher if you really have to? What is the method and what external circuitry do you need to add? Is it altogether more hassle than using ...
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53 views

Setting gain on Improved Howland current source (best practice)

I understand that you can set the gain of an improved Howland by setting the the ratio of resistors \$R_2\$ and \$R_1\$ and/or the value of \$R_{\text{set}}\$. Is it better to leave the ratio of \$...
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57 views

Howland source, MAX current output?

How would one determine the maximum current output you could achieve from an improved Howland source given a specific Op-Amp? ie. What do I need to look at in the Opamps datasheet? (I am using a ...
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78 views

Meaning of “ramp time”?

I have read that ramp means slope but what is the meaning of "ramp time" ? For example,if we have a saw-tooth wave,what will be its ramp time? Please kindly explain with figure/graphics
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56 views

Finding Rthevenin with respect to C1

Howcome when I try to find Rthevenin for Part A, the resistors in the loop L1 are completely ignored? Does current not flow in L1 in this case? Req = 60||30 ohms is the answer btw, giving us a time ...
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26 views

Role of independent and dependent sources when calculating equivalent resistance

There are plenty of topics about this question, but I did not find a precise answer. Let's consider two points A and B of a generic circuit and suppose you want to find the equivalent resistance ...
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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 ...
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3answers
197 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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101 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
60 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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363 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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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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72 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
79 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
181 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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67 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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62 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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187 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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64 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
2k 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
50 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
61 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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41 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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37 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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54 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
197 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
104 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
86 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
138 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
106 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
414 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
80 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
179 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
332 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
70 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
370 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
1k 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
653 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
1k 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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494 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 ...