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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Voltage regulation vs relative voltage tresholds?

There is a part of my circuit that uses resistance to output a voltage, in which is compared to a voltage threshold to output a digital signal. However +Vcc can vary and any voltages too far from 5V ...
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41 views

Power circuit design logic — suggestion

I am designing a board where my Microcontroller is powered by LM7805 regulator & my load requires 3.8 voltage, is powered by following voltage regulator NCP57302. ...
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2answers
52 views

Voltage regulator capacitor size

I want to use a LF33 voltage regulator to power a nRF24L01 module from a Arduino Pro Mini. I plan to power the Pro Mini with a 9V battery, then use it's 5V internal regulator to power the LF33 which ...
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1answer
37 views

How to activate relay when voltage rise threshold is reached

I've made a basic AC-to-DC converter, 120vac in, 120vdc out, used for backup power to run a 120vdc deep-well solar-electric water pump when the sun isn't shining. The AC power source for this backup ...
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3answers
84 views

How to find the positive wire on wall charger

i have a TPLINK wall charger from my old router. It's almost new and i would like to use it for my 5V regulator project. The prboem is that i dont know which of the 2 wires is positive and which ...
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80 views

LTC3355 backup DC/DC regulator output voltage sags under load in boost mode

Background For a hobby project I have designed a board using the LTC3355 DC/DC regulator to work as a power supply. I am a software engineer by trade, and I am thus totally underequipped to properly ...
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1answer
73 views

Reducing EMI Radiated & Conducted

I have a switching regulator that operates at switching frequency of 260Khz that steps down a 28vdc to 3.3Vdc. The switching regulator output will supply current as high as 1 amp for the initial 5 ...
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2answers
71 views

DC-DC converter topology

Is it possible to build a DC-DC converter by means of a piezo crystal followed by a voltage multiplier? The crystal would supply the AC voltage needed by the voltage multiplier. I'm looking to get ...
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1answer
42 views

Connecting a +12V DC wire to a Voltage Regulator with 4 pinouts

The voltage regulator I'm using has 4 pins (2 in, 2 out) pictured below. The reason I purchased this regulator is that I want to convert +12V DC in to +5V DC current for connecting a Sony Projector ...
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30 views

Discarding Current Monitor of Linear's LT3482

I've been looking at the LT3482 IC with an APD/Photon Counter application in mind. I need to bias my APD at something like ~65V to reach Geiger mode. Since I've already have a non-inverting ...
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2answers
68 views

Converting Voltage [duplicate]

I have a pair of batteries that can operate at 7.2V (series) or 3.6V (parallel) and I need to power up a device using 5V. I can use a Voltage Regulator to down voltage at 5V or I can use maybe ...
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9 views

Replacing the Voltage regulator of a fried arduino [migrated]

I accidentally fried my Arduino. I found this Instructable. The symptoms are the same. The board not powering on connecting USB source and the over current protector was heating up. So i removed the ...
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3answers
117 views

What is the minimum supply voltage for the MC34063E in step-up (boost) configuration?

I need help determining the minimum supply voltage specification for the MC34063E in step-up (boost) configuration. I can't tell for sure by reading this datasheet. First, on page 1 they say: ...
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1answer
44 views

Enable pin with maximum 3.0v

I've an Enable pin active-high that have maximum voltage rating of 3.0v, but I use a 3.3v MCU outputs. I've also a 3.0v voltage regulator on board. Should I use resistor voltage divider or there is a ...
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1answer
43 views

Beginner PCB Repair - Voltage Regulator Issue

During a fault finding mission on my car I found the Vref on a sensor that should be 5V sitting over 7V. I traced it back to one of the modules and found the pcb mounted voltage regulator was ...
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1answer
86 views

Why use two power sources when designing a voltage regulator using a zener diode

I am currently designing a voltage regulator using a 5V zener diode. I am wondering why some people choose to use two power sources instead of one, what would be the benefits of this ? the circuit ...
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2answers
111 views

Voltage regulator from 24v to 3.7v [duplicate]

I need to build a simple voltage regulator that can drop voltage from 24V(from a DC power supply) to 3.7V and supply at least 2A or more(up to 5A if possibile). Can I just use a 2 resistor voltage ...
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0answers
52 views

any voltage input to 2.7 output with ldo regulator

Larger view: https://drive.google.com/file/d/0B-OMSFFCrVLsTGdmcXVUVjlvd0U/view?usp=sharing any ideas to improve it? source voltage 2 batteries silver-oxide 1.55V, output voltage fixed 2.7V the ...
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2answers
56 views

arduino nano broken or not after reversing l7805 pins?

I tried to breadboard a project using arduino nano and l7805 regulator power by 12v dc from wall. I pluged the regulator backwards, output to 12v and input to 5v arduino pin, by mistake for a couple ...
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1answer
57 views

LM2678 Output Voltage Drop Under Load

I soldered up a LM2678 for a 5V 1A output with a 12 volt input (Input voltage and current from (12v supply @2A) like shown here. http://www.ti.com/lit/ds/symlink/lm2678.pdf It outputs a solid 5 volts ...
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1answer
52 views

Power adapter versus Power supply

I have a mini water-pump/motor hooked up to an LM338 (similar to LM317, but capable of higher current output). I set up the LM338 to create a 6.1-V output, from an 18-V input; this was done by ...
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0answers
31 views

1.25V shunt regulator help! [duplicate]

I have used TLV431 precision voltage-adjustable shunt regulator as a source of 2.48V to be used as a reference. The output of the circuit will be fed into an op-amp voltage follower. My problem is it ...
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2answers
65 views

What can cause the output voltage of a buck converter to drop (apart from high current)?

I am using the LTC3388-1 buck converter to provide a microcontroller with a regulated 1.8V voltage. I use pretty much the reference circuit as seen in the image. When I disconnect the ...
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1answer
59 views

Running a Microcontroller with Selectable Voltage (3.3V/5V)

I'm working on a non-volatile SPI memory chip programmer. My design sends individual data bytes over USB to an MCP2200 (USB to serial converter chip), then the serial data is sent to an ATMega48, ...
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297 views

voltage regulator design flaw in application?

I am a veterinarian and I need some help. I purchased two very expensive lift/weigh table/scales. After about 5 years of service one of them failed. I determined that the main PC board had failed. ...
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44 views

Negative Bias from Voltage Regulator

Can the voltage regulator from here, Figure 6 be used to supply a negative bias to an APD? Would inverting Vin/GND do the trick or could that damage the IC?
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93 views

Ground Pour in Power Supply PCB

I'm designing and building a linear power supply for my tube headphone amplifier. Considering this should be HiFi, I'm trying to make it as good as it gets within "normal" building costs and without ...
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1answer
74 views

LC filter and ferrite bead

Suppose I've a circuit that is affected by EMI noises that have a freq. less than 80khz and noises above 2ghz. I want to cut off this noise freq. before they reach my ICs. The circuit is powered by 5 ...
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1answer
100 views

Correctly choose circuit decouplers and filters and schematics advice

I want to ask some help to correctly design a power supply circuitry with TPS799 voltage regulators. I've this reference circuitry: And nothing more explainations. I want to use same specifics of ...
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5answers
243 views

Selecting input voltage for 7805

I generally use switching 12V power supplies for my circuits since they are so common, but I understand the 7805 can take a lower input voltage. If I gave the 7805 a lower input voltage (i.e. 9V), I ...
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2answers
58 views

Does the MC7805CT-BP need capacitors?

As far as I know, you have to put capacitors on most voltage regulators. However, the data sheet for this one specifically says "No external components required" and furthermore goes on to state ...
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52 views

My attempt at designing a ripple regulator - will this work?

I am recently getting into electronics design and learning about all this fascinating stuff. I wanted to challenge myself to build a ripple regulator that can take the output from a series of solar ...
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65 views

Is it efficient to run a linear regulator in dropout mode?

In a battery powered application, it might be tempting to run a LDO in dropout mode as a LiPo battery falls from 4.2V to below 3.3V. Is this a normal thing to do, and would most regulators perform ...
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4answers
90 views

TLV431 precision voltage reference [duplicate]

I have used this circuit from the TLV431 datasheet and replaced the values according to what I need which is 2.48V. This output will be directed to an op-amp as a reference. My problem is I can't ...
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1answer
84 views

Voltage regulator like LM 317 which can interface like SPI or I2C

Is there any variable voltage regulator IC similar to LM317 available the output of which can be programmed through a digital interface like I2C or SPI?
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79 views

Precision Shunt Regulator Increasing Voltage overtime

I want to have a stable voltage of 2.47V using TLV431AC which is a precision voltage-adjustable shunt regulator. http://www.ti.com/lit/ds/symlink/tlv431b.pdf I am able to get it by putting a 5k ...
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2answers
159 views

Voltage regulator up to 100v? [closed]

I want to make a power supply that outputs 90v DC, and I was looking for a 0...100v voltage regulators, but I don't find any...? How can I achieve this if I can't find them? The input voltage of the ...
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1answer
87 views

Cheap and easy way to power MCU from Li-Ion, and keep it powered during charging

What is the cheap and easy way of powering MCU from Li-Ion battery, with automatic 3.3V regulator disconnect while charging, to properly charge the battery? I've came up with something like this: Is ...
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1answer
53 views

Choosing Correct Switching Power IC for 5v 2A Output from 2S Battery

I am designing a Power Circuitry for a Application that needs to feed 1x Beaglebone Black (5v), 1x Device with 600mA (5v), and 2x XBeePro Modules (3.3v) via a 2S (7.4v 1Ah LiPo) Pack. The Plan ...
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1answer
88 views

Reverse current protection for a battery operated circuit

I'm planning a hobby project with the following characteristics 3.3V circuit, battery operated (by regulating standard AAA batteries) Most of the time in "sleep" mode, so I need very small quiescent ...
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1answer
53 views

Running 6 LEDs off 3s (12.6v) and 4s (16.2v) battery

This may be a very simple question but I want to run 6 LEDs on a PCB and I know I can run them simply off a 12.6v 3s battery but if I want to run a 4s battery 16.2 then I will need some sort of ...
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1answer
42 views

Source with variable output impedance / Fast large signal voltage variable resistor

I need a source that has an adjustable output impedance. Corner parameters are: Voltage range: +-5V, large signal BW > 10 MHz, output impedance range at least 1k to 500M. Larger would be better. A ...
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1answer
105 views

How much resistance will I need to drop the voltage?

9 Volts is applied to circuit. There is an LED which runs on 3 Volts. I want to drop 6 Volts. how much resistance (\$R_1\$) would I need for that?
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3answers
89 views

Detecting transient voltages in a wall wart

Background I have now three smartphones (SGS3 [neo], max 77686 or so) lying around, all more or less dead due to a broken voltage regulator. Since I am not a fan of coincidences, I suspect a broken ...
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2answers
107 views

Rectifier for 3A load [closed]

What kind of rectifier circuit would I need to build a 25-30V 3A power supply with an input voltage of 24V AC?
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1answer
42 views

-1.2V from LM337L negative regulator?

Here is the datasheet for this device: TI LM337L, at the 3rd page there is an equation for calculating the resistor needed in the voltage divider to set the output. -Vout = -1.25 * (1 + (R2 / 240)) ...
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69 views

How do physical connection interfaces handle floating voltages

I am sorry if this is a bit of a novice question but I am new to electronics and have come to a problem that I can't quite see an obvious answer for. A while ago I had a bit of a scary encounter when ...
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2answers
81 views

Power supply draft advice

I've attained most of the material I need to build my first power supply. The specs are mostly dictated by the parts I have. My intention is a dual isolated variable output power supply that I can ...
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3answers
65 views

Filtering the output of the “cheap MCU voltage inverter”

This is the circuit I have to create a negative rail for a local op-amp which needs the rail in order to manage to get low on the output rail. I've tried running a single supply but that did not ...
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2answers
73 views

How to run ATmega328P-PU using 3.7v Lipo 600mAh?

I want to run bare ATmega328P-PU using 3.7v 600mAh Lipo Battery. The Lipo is used to run Nano Quadcopter. The discharge rate is 20C. My Question is: 1. Will connecting Lipo to my atmega directly fry ...