# Questions tagged [voltage-drop]

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### DC-DC Converter voltage drop on load [closed]

I bought a DC-DC converter to charge my devices with the 20V 1Amp current of my solar panel. I set it so it would convert to 5V but when I connect to load the voltage drops to 4.7V or less depending ...
26 views

### Voltage Drop Formula for Three Phase Power Systems

I've just started learning about electricity and power systems, and am currently learning about calculating voltage drop for three phase power systems. The book I am reading is explaining how to ...
18 views

### MPPT charge control voltage drop

What would explain a voltage drop on the load side of a MPPT solar charge controller? My power source is not actually a solar panel, but a 12v 300watt DC power supply. At present there is no battery ...
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53 views

### How to prevent voltage spike from BLDC motor in ESC circuit

I'm implementing the circuit below by modifying it using STM32 (Bluepill) and adding some decoupling capacitors (100nF) to the bluepill and LM339 with the supply from the battery also connected to the ...
43 views

### Is there a spec for maximum voltage drop to a motor at startup?

When an induction motor starts, it pulls more current than when continuously running. Current flow causes voltage at the terminals to drop. At some point, the voltage drops too low to successfully ...
54 views

### Question on resistor voltage dropper values for VCC supply of LED driver IC

I was designing the PCB for a 10 W LED driver with the AL1676 controller. From the datasheet, the application circuit shows that the driver takes its VCC supply through R1 and R2. The maximum value ...
• 1
53 views

### How to calculate capacitor size to mitigate voltage drop caused by current peak

I have a system that is powered by a 3V battery. I want to add a buzzer that will take 30mA for 0.1 seconds, so I'm experimenting with capacitors to prevent voltage drops from the current peaks as ...
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1 vote
96 views

### Edited: What are the causes of a 48 V, 10 Ah Lithium-ion battery's output voltage dropping to 0 V with a 200 W load?

First of all, please accept my heartfelt greetings to the members of this community. I have been a user of this site for so many years, yet this is my first query. I recently asked an Electric Vehicle ...
1 vote
166 views

### Difference in wire gauge for three phase and single phase domestic power supplies

I'm trying to understand why the recommended wire gauge for a domestic supply depends on whether you're getting three phase or single phase power. Specifically I'm talking about when the power rating ...
54 views

### Is the voltage drop smaller in three-phase circuits?

If the same power and the same distance are used for a single-phase and a three-phase circuit. Will the voltage drop of the three-phase circuit be smaller?
91 views

### Running 230VAC LED module at 400V

I'm looking at a feedback LED from Eaton (their part # M22-LED230) which is rated to run at 85-264VAC. I'd like to use it to indicate if there is voltage present across 2 phases of a 400V 3 phase ...
51 views

### MAX889 Output voltage dropping

I am using MAX889TESA+ for generating -3.3V from 3.3V input. The schematic is as below. I am feeding the output from this regulator to the 8 sets of AD8066. When the 1 set of AD8066 is connected the ...
94 views

### The difference between voltage drop and voltage regulation [closed]

An ideal voltage drop (VD) is 0% Similarly, ideal voltage regulation (VR) is 0% Both give the change in voltage between full load and no load. The difference I know is that VD is related to cables, ...
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157 views

### DC-DC Converter Dropping Voltage Under Load

I have a DC-DC Converter that is rated for an input of 9 to 36 V and an output of 12 V, 6 A. When under no load, the DC-DC Converter outputs 12 V as expected. When under a load of one motors (0.037 A ...
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118 views

### Voltage drop on power input to four-layer PCB

I would like to preface this post by saying I have no formal education or training with electronics and am completely self-taught. I really enjoy designing home brew computers from the late 70's and ...
125 views

### TTL voltage drop

I recently bought a lot of TTL components like 8-bit registers, bus transceivers, etc. to build an ALU and 2 registers. My issue is that when I build a register, the voltage drops to 4.2, sometimes ...
37 views

### Battery voltage drop on load (speaker amplifier)

I have recently built a Bluetooth speaker. It is working well, but there is a problem when playing on high volume. The speaker has 2 parallel 18650 batteries for a power supply. I used booster modules ...
70 views

### MIC2251 5V Booster - voltage drops when load is connected

I have a step-up circuit that boosts 2.8-4.2V on the input to 5V. The problem is when I connect any load to it at the output, it loses around 1V and I have no idea why. The Step-up IC is MIC2251: ...
• 55
49 views

### How do I size conductors to a three-phase induction motor to account for voltage drop?

Suppose I have a 480-volt nominal electrical distribution system, and a 460-volt nominal motor. Assuming +-5% variation in the source, it could get down to 456 VAC. I've seen references to motors ...
183 views

### Why does Raspberry PI reduce input voltage on GPIO Pin?

We have a cadence/pace sensor for a bike, and we want to retrieve the "sin" by plugging it to a GPIO Pin of a Raspberry PI. The signal "sin" has a voltage that varies between 0 and ...
• 1
136 views

### Voltage drop across transistor (Vce) vs LED load forward voltage

So I'm trying to simulate a BJT switch for an LED. Here's the detail and how I setup the simatiomln. Vsupply = 4.2 V LED UV Vf = 3.6 V Hfe = 100 Here's the simulation: Falstad link, does it work? ...
156 views

### APA102 LED strips behaving weirdly and flickering towards the end

I am trying to make a 29 x 29 LED matrix to display animations using the APA102 (Dotstar) LEDs with an Arduino MKR Vidor 4000 as a microcontroller. I have connected the data and clock signals of the ...
104 views

### Dropping solar panels' input voltage to a solar inverter by approximately 10 V

We installed a solar panel array at our house. The total output of the solar panels is around 465 V DC with open circuit. the DC Input limit of the solar inverter is 450 V DC. I want to lower the ...
• 1
160 views

### Is there a way to somehow "isolate" a voltage drop?

I have a small issue with voltage drop. I'm working on a project, where I have five resistive wires (approx. 8 ohms each) connected to li-ion battery pack in parallel. The battery pack outputs 16.8V ...
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58 views

### MOSFET voltage drop seems way too high

As discussed here, I'm trying to use a MOSFET for reverse polarity protection. I got an IRFB7440PbF, which has a low Rds(On) (2mOhm,) suitable Vgs (I'm using a 5V power supply,) and what I thought ...
• 177
28 views

### What is the most accurate method to calculate wire cross section according to voltage drop on AC distribution systems?

If we go for the intuitive way you should first calculate resistance of conductors based on temperature and construction properties but I don't get how to integrate that with the format of current or ...
1 vote
96 views

### Battery Voltage Dropper

simulate this circuit – Schematic created using CircuitLab I am looking to understand this circuit better. The main question is: Is it true that the battery will start draining and stop when ...
96 views

### the sound from the coil when the current is drawn

I have buck-boost converter using a TPS630250(4.2 ->Vin) - (3.3 -> Vout) in my PCB. This buck-boost converter can draw max 4A in buck mode and max 2A in boost mode. While there is no load or ...
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1 vote
66 views

### Large voltage drop across source terminal

I am using an N-channel MOSFET to enable another IC. My gate voltage=1V, the drain voltage=3.3V. After rigging up the circuit, the voltage across EN_DC23 was measured with reference to ground and it ...
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320 views

### Measuring voltage drop across 10 ohm, 100 ohm and 10 kilohm resistors (one at a time) - very simple circuit

Below is a picture of my very simple circuit. There are three resistors 10 ohm, 100 ohm, and 10 kilohm. I connect them one at a time in serial fashion and measure voltage drop across them. When I ...
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74 views

### Why is the voltage drop over my MOSFET so large?

I am trying to use an NCV8403B N-channel power MOSFET to control the power for my circuit. The schematic itself is quite simple: The MOSFET is controlled by an SPST switch. When in the ON position, ...
359 views

### How to limit current for a transformer?

So I've been winding and unwinding, all to get the current right but it's not going well, so I'd like to know how I can limit the current going into the primary side of my transformer, since the ...
80 views

### How to calculate the voltage drop in this case?

I started with the superposition principle. For Vcc, Ib is open circuit and Eg is shorted. I got that the voltage drop due to Vcc is 10000/3 V. For Ib, Eg is shorted as well as Vcc. Since Ib is dc ...
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98 views

### How to prove that the $3$ nodes have the same potentials?

The question of symmetry. The each resistor has the same resistance(given by $r$). Why a current doesn't flows between the each endpoints of the middle $2$ resistors? The text book only states of ...
84 views

I've got a motor driver controller, I found an SMD component that is the same component shown in the picture. I need help identifying this component. I've tried to google the part number, but no luck.
1 vote
51 views

### How this equation of the voltage is attained?

I've may been asking the very easy question. The each resistor has the same resistance(given by $r$). The textbooks states the following. $V_{AB}=r\{i_1+i_2+i_3+(I-i_1)\}$ How the above equation ...
57 views

### House refurb rewire - low current?

So we've been renovating (virtually new everything) a 1930s semi that hasn't been modernised since it was built and hadnt been lived in since the 70s. Naturally a full rewire was high on the agenda ...
• 1
170 views

### What factors affect the voltage drop in a basic ac generator when an additional load is added in parallel

As a preface, I am in school to become an engineer on a ship so my question relates to a self-contained circuit/grid and not a home. We are going over generator theory and how an automatic voltage ...
229 views

### Understanding voltage drop on a transistor

I've been reading different answers online and am trying to get my head around calculating transistors. I have a circuit like this: (Imagine the base goes to a microcontroller and is connected ...
72 views

### Drop 12v down to 6V [duplicate]

I want to power 3 x 12v 0.2A PC fans from the Molex power supply on my PC PSU, the only issue is that I don't want them to run at full speed. So I am trying to half the voltage to 6v. I have built ...
56 views

### Fixed voltage drop (current and temperature independent)

simulate this circuit – Schematic created using CircuitLab Is there a clever way to create a fixed voltage drop say 2V that is not affected by current or temperature? Voltage stability should ...
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46 views

### about the high voltage capacitor found in charger circuit

A while ago i have opened an electronic balance charger for a reason to try understanding how the circuit works so I've drawn the entire circuit for that purpose but i no longer have the drawing, but ...
251 views

### Voltage drop when connecting DC-DC booster XL6009 to my solar panel generating 10V constant

I have connected my solar panel (rated 6 V 3 W,) but it is generating approximately 10V. This 10V is fed to an XL6009 to generate ~15-166, which is further fed to a 4S BMS to charge. I checked that ...
• 1
1 vote
298 views

### Voltage drop on lithium batteries

Is there a difference between having one big battery vs 2 batteries in parallel? I am building a "fan controller" and want to power a 12V fan with a lithium ion / polymer battery. The ...
1 vote
80 views

### Where voltage is lost in an emitter follower?

I'd wanted to know what happens in an NPN emitter follower with ${\delta}V=Vcc-Vee$. At which junction does voltage drop? May this drop be fatal to a transistor?
97 views

### Dramatic voltage drop issue

I'm using this circuit design: Link to original project page with schematic on EEVblog forum I changed some values: R1:220 ohms R3:470 ohms C1:470pF M1: TIP41C. When I turn the converter on and ...
101 views

### AC-DC Powersupply voltage drop

I just bought this power supply for a project. I just went in with a multimeter to test the voltage and pins, which gives me a 20V reading as expected. However, after I remove the power supply from ...
1 vote
91 views

### Voltage drop problem. Transistor, optoisolator, relay for programmable Christmas lights?

I'm trying to create programmable Christmas lights - a very simple circuit controlled via Arduino or NodeMCU. My problem isn't on the microcontroller side, but the basic electronics. Now... I have 2 ...
1 vote
456 views

### What is the best way to parallel two shunt resistors using a switch?

What kind of switch in place of SW1 will have minimum amount of error in current readings? Max current is 10 A and we should be able to control the switch digitally. simulate this circuit – ...
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