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Questions tagged [voltage-regulator]

A voltage regulator is an analog circuit that produces a stable output voltage that doesn't vary with input voltage or load changes. Switching regulators are much more efficient than linear ones.

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On a 3-terminal bench power supply (+, -, GND), are there positive and negative drivers behind each of the terminals?

In a 3-terminal power supply like this, are there individual regulators behind the positive and negative terminals? For example a LM317 on the positive and a LM337 on the negative? If not, what kind ...
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Using internal regulator DVDD pin to power up external devices

I am designing a H-Bridge PCB and using DRV8323 as the driver. This chip has a pin name DVDD which from my understanding, from the below statement, is used to ...
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34 views

Why does the output voltage of my linear gain amplifier depend on the JFET gate voltage?

I am trying to build a linear gain voltage controlled amplifier using an N-channel JFET as a voltage variable resistor (see circuit below). As the circuit is set op now, I would expect Vout to be ...
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58 views

24V DC to +5V and -5V

I need to convert 24V DC to +5V and -5V to power two op-amps (opa2134) and one ATtiny85 with minimal heat generated from the circuit. What voltage regulator would you recommend ? //Digis
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Current Controlled Potentiometer

The core problem I am having is that I need to be able to control a DC to DC voltage regulator based on input from a 4 to 20 mA signal. The end goal is to have the output voltage of this regulator be ...
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35 views

60V 5A Buck converter for CC/CV application

I need to charge a 14S LiPo from another 14S LiPo. The easiest way would be to buy a buck-boost converter with a current limitation, but I couldn't find a single one keeping up with my specs. So I ...
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53 views

Why does adding a capacitor to the adjust pin of a voltage regulator improve PSRR?

When looking into the datasheet of an voltage regulator, they often recommend adding a capacitor from the ADJ pin to ground, to improve ripple rejection. It can also often lead to an significant ...
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Simplest and chepest way to provide 3.3V@150mA from power supply running at 6Vrms@120mW

I have a power supply that can provide 6Vrms (50kHz) and 130mW max (maybe a bit more). Unfortunately, for my project I need a peak of 150mA in 3.3Vdc (ESP8266) in regular basis during TX but most of ...
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67 views

Current-limit circuit for 78XX voltage regulators

I need to find the value of Rsc and R1 in the following circuit: In this circuit, Q1 is the high-current pass transistor. Its emitter-to-base resistor has been chosen to turn it on at a given load ...
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52 views

Bypass a linear voltage regulator by applying a voltage at the output while input is not connected? [duplicate]

Question Is it safe to "bypass" (as in circumvent) a linear voltage regulator by applying a voltage to its output (equal to the specified regulator output voltage), while the regulator input remains ...
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344 views

Things to avoid when using voltage regulators?

My project has components that operate at 3 different voltages (9, 5 and 3.3). I would like to only deal with one power source. Is it alright to feed one 12 V power source to 3 voltage regulators? Is ...
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53 views

±5V using Voltage regulator L7805 and L7905, from DC input

I am trying to get ±5V using voltage regulator L7805 and L7905. The datasheet says to use AC source as input and transformer, but I am not really familiar with transformers, and I don't know if I can ...
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17 views

altium input/output pin error

I have a problem (stm32f407vgt6) with altium input output pin error. I will use 3.3 volt in my mcu that's why I added 5-3.3 voltage regulator in the circuit but I ve taken this error. Details VCC0 ...
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71 views

Load resistance in voltage regulator

I want to find the minimum resistance \$R_L\$ so as to maintain \$V_z\$(voltage of the zener corresponding to the minimum current \$I_{z_0}\$) across the same resistor \$R_L\$. simulate this circuit &...
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LM2937 Replacement/Upgrade Thermal issues

We are using an LM2937-5v LDO regulator in an SOT223 package - currently flowing approx 150mA with a 14V input (9V drop over it), and, as you can imagine it gets quite warm: 70degC (though from my ...
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44 views

What could be the output current rating of the following shunt regulator?

I am trying to solve the 2013 paper set by ISRO for electrical engineers. I wanted to verify if my answer to Question no 18 is correct. So \$I_L\$ is being drawn out of the circuit shown. Since the ...
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76 views

First ever MOSFET use, is my schematic correctly using it?

I want to build a hybrid board that can either be powered by unregulated 9-15v power supply, OR, by a regulated one (that is to be also powered by a li-xx battery and also to charge it using a ...
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290 views

LM22678 Unstable output

I am building a voltage regulator with the LM22678-5. I used TI WE-Bench designer to get the component values needed for the regulator: The regulator outputs 5V when there is no load however it ...
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76 views

Capacitor in the circuit - Bypass capacitor

I was trying to measure the supply current of a CAN transceiver during fault conditions, one thing which I noticed was that during CANH to GND(when the current consumption is supposed to be the ...
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1answer
53 views

Why does not all the current flows through Zener diode?

Let's assume the following circuit, where Zener diode is used as a voltage regulator. R16 (R18 later) is the load. When the input voltage is sufficiently high for Zener diode to be reverse-biased, ...
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1answer
112 views

Using a zener diode to limit current to an IC for various input voltages

I'm designing a board based on TI's DRV110 solenoid driver. The datasheet explain that: "The DRV110 is able to regulate \$V_{IN}\$ voltage from a higher external supply voltage, \$V_S\$, by an ...
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Powering and regulating supply DC voltage for a digital MEMS microphone

I want to use Infineon IM69D120 microphones [1][2] in an array (about eight of them), and I am confused as to how exactly (with which components) should the MEMS microphones be supplied. I chose USB ...
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So I bought a 3.2VA 15V transformer instead. This should do a better job for the voltage regulator? – [duplicate]

Voltage regulator not outputing desired voltage and extremely hot This means that there will be only something like 700mW of power so no heatsink is needed.
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Cooling Methods for Voltage Regulators

I have a NCP1117 5V voltage regulator that is on an Arudino Mega. The Arduino Mega, with all of the necessary electronics parts for the project, draws around 200mA when operational. When using a ...
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82 views

Voltage regulator and loss of ground

I have a design that has a +24VDC supply, a 7805 voltage regulator converting it to 5 volts and then a microcontroller and some peripherals behind the regulator. The design and the 24V supply ...
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1answer
62 views

Voltage regulator - unexpected voltage drop, is this normal?

I am using this voltage regulator. Following this example: For input power source, I am using old SATA convertor power adapter, which produces 12V 1.5A max (I tried various power supplies, all ...
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1answer
58 views

Is there a SSR like device that can switch at kHz frequencies?

I'm designing an industrial control system that incorporates several peltier devices. As I understand it, these devices are more efficient when driven with a constant voltage, vs being cycled every ...
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1answer
37 views

Linear regulator operating point over input DC Sweep analysis

I'm sweeping the linear regulator input voltage on DC using Spice from 0V to maximum expected Vin. However, as the OTA that makes part of LDO is internally supplied by the output voltage, the ...
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57 views

Linear Regulator Operation

I have a linear regulator with three pins. It's identifier is LM7805. I've taken a look at it's datasheet and it looks unlike linear regulators I've encountered. Is the the op amp circuit included in ...
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2answers
52 views

voltage booster current draw

My input source is 3x1.5V alkaline batteries. The input power supply is then connected directly to a 12V voltage boost regulator. I used my multimeter to measure the current draw of my load and it ...
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2answers
83 views

How to regulate voltage of transformer output for nichrome wire

I have a basic CNC machine for cutting EPS foam which uses about 9.5in/23.5cm long straight 28 gauge Nichrome wire as the cutting element. The nichrome wire is powered independently with a 220V-36V 5A ...
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Why peak output current is greater than short circuit output current in 7805 voltage regulator?

This is the datasheet of 7805 voltage regulator produced by "Continental Device India Limited". Question: Why is the peak output current greater than short circuit output current? Shouldn't the ...
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68 views

MC78M12 voltage regulator without bypass capacitors in a simple PCB with only analog signals

I have a very simple board, two layers, two gnd polygons, 8 analog inputs incoming from 8 potentiometers and 8 analog outputs. In the PCB are 2 resistors (R1||R2) between input and ouput. So, output ...
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3answers
60 views

would like to verify a filter design I need to make for a backup camera in my truck

I am installing a backup camera in my truck. I am getting some source of electrical "noise" in the electrical system in my truck and its not allowing the backup camera to operate. Let me explain a ...
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1answer
93 views

Easiest (or cheapest) way to get both 5V and 3.3V on one circuit

I'm working on a circuit based on an ATTiny85 and I need accelerometer input. I was looking at using an analog accelerometer (KXTC9-2050 that runs around 240 uA) because I have the extra pin and I'm ...
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2answers
73 views

Avoiding DC voltage drop for surveillance cameras over long distances

Trying to power 2 HD-TVI cameras 800 ft away from my home office. The wall mounted adapter provides 12v DC at 1 amp. I am looking for a good solution at the lowest possible cost. There are ...
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1answer
42 views

Calculating the minimum and maximum \$R_{load}\$ for a zener voltage regulator

So, I have a generic zener voltage regulator with \$R_{s}=650Ω\$, \$V_{in}=15V\$, I'm using the zener BZX55C8V2 (datasheet). From the datasheet the test current is \$5 mA\$ and the maximum zener ...
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29 views

SMPS topology for combination of current controlled rail and fixed voltage rail

I'm looking at designing a LED driving power supply that can interface with a universal AC main input (~90VAC-260VAC) and produce 2 rails at the output; one a current controlled rail, and the other a ...
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2answers
2k views

Voltage Regulator Design Not Working

I have attempted to design a 12V to 3.3V switching regulator for my PCB that will draw 0.5A Max. The problem is that after assembling the components, the output voltage is the same as the input ...
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2answers
64 views

Is it a good idea to use the motor voltage as a source for a logic regulated voltage?

I'm creating a circuit for controlling a NEMA17 step motor with 1.7A per phase. This motor will be driven with +12V. The logic part of the circuit will use +5V though. At the beginning, I was ...
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1answer
55 views

12 Volt DC Power Supply set up

Can I connect a 12 volt DC regulated switch mode power supply (good voltage control) in parallel with a 12 volt DC car battery (great amp supply) to supply the extra current need to run my RF-...
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1answer
38 views

LTC3588-1 circuit model LTSpice export

I would like to use the LTC3588-1 component native to LTSpice in SIMetrix, however I am struggling to find a way to handle the export/import. Is it possible to export a component from LTSpice in a ...
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2answers
47 views

L298N H-Bridge : Powering 4 motors using (6) aa batteries vs (4) aa [closed]

I am currently wiring up my raspberry pi, H-Bridge and (4) 3-6v ratting motors. My question is, how will performance change based on me using 6 or 4 batteries to power motors? I noticed some tutorials ...
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4answers
119 views

Too low efficiency with “0-30V 2mA-3A DC Regulated Power Supply unit with Continuously Adjustable Current Limiting Protection” PSU kit [closed]

I ordered and assembled the kit (link and image added below). Everything works fine. But as everybody knows, it requires a great heat sink for the regulator. The ordered unit costs less than $5, but ...
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46 views

Boost converter output voltage error

I'm using LT3494a to generate 37v from 6v input. This is my circuit. According to the datasheet, this chip can provide up to 40v output, so it should be able to generate 37v. Also, the simulation ...
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1answer
57 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
71 views

Vary the Vpp of sinusoidal oscillator

For an assignment I have to create a sinusoidal oscillator with 5 Vpp (centered around 0 V) oscillating at 10.0 kHz. The oscillator works as expected, at the right frequency, but the voltage needs to ...
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3answers
131 views

Right reasons for using a voltage regulator for DC motors

I read in an online book at https://www.learncse.com/images/Lessons/Lesson_14.pdf following reason for using a voltage regulator to power DC motors. While I understand the importance of using a ...
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2answers
87 views

High Voltage Regulator

I have built a valve/tube tester. To provide the various screen and plate voltages I'm doing this: The required voltage is selected by a rotary switch down the stack of zeners. The momentary button ...
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77 views

Voltage controlled voltage regulator?

I have a voltage that's used to dim a 12V bulb and I'd like to use it to dim an LED instead. My plan so far is to use a triangle generator and a comparator to make a PWM signal with varying duty cycle....