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Questions tagged [current-source]

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An electronic component that sources current - if it sinks current it is called a current sink but both devices (sinks and sources) can be called sources. An IDEAL current source will supply current, maintain high voltage compliance (i.e. adapt its output voltage to match the network it is supplying current to) and have an infinite output impedance. In non-ideal implementations current sources have limited operating ranges and finite output impedances.

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I want to learn how to design a simple current source using a BJT. I found this picture on another site (https://www.wellpcb.com/blog/pcb-projects/constant-current-source/?utm_source=chatgpt.com), but ...
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Texas Instruments Documentation told me that through the R5 resistor flows a current of 1.3 mA independent from the input voltage. I am trying to use PSpice for modeling, but the results are different ...
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I am having trouble forming a clear definition for a source component versus an active component. From my understanding, an active component is one which can supply power to a circuit, but may also ...
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I need to read the light intensity (from 20lx to 900lx) in a room with a microcontroller. Then turn on lights if the luminance in the room is lower than an adjustable threshold. This is the current vs ...
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At the beginning, I wanted to say that English is not my first language, so I'm sorry for that. Also, it's probably a very stupid question, but I just want to know. Lately, I've been trying to learn ...
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I think I'm overlooking something very basic in this problem but I'm having trouble determining what that is! I'm pretty sure the issue is stemming from my equation for mesh 1, but the assumption I ...
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I'm struggling to understand why, depending on the type of source (AC current or AC voltage), I can see peaks corresponding either to system resonance or antiresonance. I'm looking at the current ...
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I am dealing with a setup where resistance of a resistive DUT (Device Under Test) is measured by sourcing some current through the DUT from a current source and by measuring the voltage drop across ...
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I have always had this confusion, and I'm finally ready to ask it, after reading the answer here: https://electronics.stackexchange.com/q/755447 There are many questions here that seem tangential to ...
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Long story short I see an oscillation in current in my loads, I can fix it by adding an additional diode, but would like to reproduce the issue on LTSpice to confirm my solution addresses the problem ...
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I'm trying to build a 2A current source with low noise and lowest drift possible. This circuit will be powered from batteries and the load will be some chemical solution with total resistance of ...
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I've been looking for the topology to realise this for a few weeks now and haven't been able to get where I want to be. Essentially I have a 0-3.3V input voltage (Vctrl) and want to output a ...
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As far as I know the linearity of any element is given by the superposition principle meaning if it satisfy the superposition principle therefore its a linear one Meaning if $$f(x_{1})=y_{1}$$ and $$f(...
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I am having trouble understanding this problem. The book says that all three (assume ideal diodes, no voltage drop) diodes are conducting and the currents I solved for are correct. However, I don't ...
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My thinking is that at t = 0 s, at the sudden change in Vs, the capacitor will act as voltage source of 2 V and thus applying KCL at node X, we can get a Vx = 4 V. My confusion is what will happen at ...
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I am trying to design a digitally controlled current source but I have doubts regarding whether the driving of the Mosfets in the Blue box is correct or not , I understand that for example when the ...
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So here how I get it, it is the drains of pMOS and nMOS are shorted, which implies it is like two current sources joined and both have same direction. For (a), to ensure that both the saturation ...
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so I am trying to simulate and eventually build a High Compliance Voltage Current Source. The design I am trying to implement is based on the paper: Ultra-low noise, bi-polar, programmable current ...
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I will try to summarize my problem the best I can. I have a circuit I use to generate a voltage pulse. This circuit consists on a voltage-controlled current source with a 54.9ohm shunt resistor, a PNP ...
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my coworker and I and struggling to implement a current driven pneumatic pressure control valve. We have an IMI-Norgren "VP50 Series proportional pressure control valve" with 4-20 mA command,...
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I have been learning how to model IC's in LTspice so that I can build my own components when needed. I am currently building a V/F converter based off of a Turkish paper my mentor gave me. This paper ...
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According to the guide CN0540 24-Bit Data Acquisition System for IEPE Sensors by Analog Devices, the LT3092 can be used to supply 4mA to an ICP/IEPE sensor if configured like this: The datasheet ...
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Why do we need to inject a current to turn OFF the DC/DC module instead of just shorting to GND? https://www.wallindustries.com/wp-content/uploads/2019/03/DCMSD04.pdf I see similar requirements in ...
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I have to solve an exercise involving a common source + common drain two-stages amplifier. The circuit is this: I cannot find a proper way to calculate Vd of the first transistor (M1). In the DC ...
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Voltage sources are predominantly found in nature comparing to current sources. However I was wondering which electrical devices made from humans can emulate a current source (very high input ...
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This is a follow up of my previous question Current boost converter and as stated in the answers the issue with the current boost converter technology is the inductor who is in series with the ...
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I am a bit confused about simplifying the current sources in the leftmost branch. I was told that the current in the branch (as shown in the photo) would be zero but how is that possible? Current ...
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I have designed a current buck converter. The idea is that you the (voltage) buck converter and you take advantage of some symmetries of electronic elements, the capacitor is to a current source what ...
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I am trying to design a Howland pump for a sine wave from 100 MHz to 300 MHz. I am using THS3091 for this. I want to use a capacitor as a load to charge when input > 0 and vice versa. Initially, I ...
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I am trying to implement a Howland current pump for high frequency applications ( Let's say 100MHz to 1GHz input signals) Basically I am passing the input signal through an RC differentiator and then ...
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I am trying to control the slew rate of a reference source for a frequency synthesizer(PLL). The reference source will be the input to the circuit below and the Howland current pump will charge and ...
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My task is to make a slew rate controller ( determined by the user) of a high frequency periodic signal while maintaining same amplitude and frequency. So if a periodic signal is given as input, the ...
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I’m designing a constant current (CC) power supply using a DC-DC buck converter with a differential amplifier for current sensing as shown in reference design https://www.ti.com/lit/an/snvaa85/snvaa85....
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Source In this circuit, the Schottky diode is used to clamp the SW node when it goes negative. From my understanding, the SW node becomes negative when the internal switch of the LT3468 opens, due to ...
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In my design, I would like to use a constant current source pin from component A, which is normally used to drive an external LED, to activate the enable pin of another component, component B. Here ...
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I'm trying to make a current source using the following schematic for this laser-diode using an OP284 opamp and a TIP120 without heatsink: Since the laser-diode have no SPICE model I used two 1N4001 ...
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I am currently working on a university project and need help with a LTspice simulation. I have two different .csv files. One describes the input voltage and one the input current, meaning that both ...
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I have a current source which supplies various current to a load as described in the pic below. I was in a situation where I was opening the current source at point A to take some measurements across ...
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In order to analyze how the circuit works, we need to use the superposition principle because we have two sources and we need to make assumptions about when the diode \$D_1\$ is ON and when the diode \...
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I genuinely don't know how to approach this. I understand ideal op-amp assumptions but I don't know how to apply them or whether I need to apply them here. The hint I got was to find the right KVL ...
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First of all, thanks for clicking this post. This circuit is a +12VDC load switch and a load takes 100mA. To simulate this circuit, I put a random valued resistor as a load. But the simulation ...
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I came across the circuits below in one of the videos on the YouTube channel All Electronics. It was sketched on the whiteboard. YouTube Video: THD - Total Harmonic Distortion I have tried to ...
Isay's user avatar
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I am trying to design an ac current source. It should output a current of 30 Arms at 50 Hz and have no more than 12 Vrms open circuit voltage. The current is fed into some device under test (DUT) and ...
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I am working with an 8x6 RGB LED matrix with common cathode LEDs on a PCB. I can select one column at a time by grounding its common cathode, and I source the current through the rows. The whole setup ...
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I stuck with this question : We got current meshes: I attempted to create a supermesh for I2 and I3 , and a separate regular mesh for I4 To complete the matrix, I added two additional KCL equations: ...
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Working on a project with a source USB type C port. Below are the criteria: ESD protected D+/D- and VBUS Source only port, will not accept power input 3A power capabilities, with the ability of the ...
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Dependent sources confuse me. We were taught a method using input and output resistances to find out whether a dependent source is VVVS, VVCS, CCVS, CCCS. Apparently for a voltage controlled source if ...
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Is there such a thing as a "passive" bootstrap? C11, R21 and R22 in the current source of Douglas Self's Blameless Class-B Amplifier (Fig 33 in http://douglas-self.com/ampins/dipa/dipa.htm) ...
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Consider the circuit below. If I apply KVL, I get V=5. If I use superposition then V=-5. What have I done wrong?
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I am simulating the following voltage-controlled current source using LTspice. This design works for the application where it is going to be applied. However, the output current is not completely ...
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