Tagged Questions

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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31 views

1A Voltage Regulator - Maximum or output?

I want to design a circuit that has 12V1A output from a battery. I am using a 12V voltage regulator Do I want a 12V 3A Regulator or 12V 1A regulator? If a 12V 1A voltage regulator gives me a better ...
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0answers
20 views

Power with Battery + 1wire to i2C

I'm creating a project with Raspberry PI B+ where I will get energy from a truck (12~27v) or/and a solar power (6v 5.6w) to charge a battery and keep the device running until the battery finishes or ...
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0answers
34 views

AC to AC Voltage Regulater

Building a hobby related very small and simple project. Currently I run 120V through a household dimmer that feeds an AC to AC (3amp, 25.2VAC output) transformer. Problem is the circuit doesn't seem ...
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3answers
101 views

Can I put 2 voltage regulators (5V) in parallel to dissipate the heat better?

I connected around 10m of christmas light LEDs to a 5V voltage regulator (lm7805). It gets quite hot, put I can still touch it without burning my finger. So in is within its temperature range (120 C ...
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2answers
34 views

Simulating a linear voltage regulator with ngspice

I am trying to simulate a simple linear regulator using gschem and ngspice. However, my output voltage varies by over a volt as my input voltage goes from 10V to 20V. Can I reduce this swing in the ...
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0answers
68 views

Help identifying a voltage regulator

I'm trying to build a portable screen so that I can watch movies around my apartment if I need to move away from my TV screen (think a WiiU gamepad or a tablet). I have many raw components and I think ...
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0answers
32 views

Step up /Step down converter [closed]

I'd like to build a DC/DC converter with the following characteristics: -Vin: 15V to 10V -Vout: 11V (if Vin is less than Vout then Vout should be equal to Vin) -Ioutmax: 8A I've tried designing a ...
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2answers
60 views

Differing voltages with the same ground?

I have a battery powered radio controlled aircraft. The aircraft runs at 16v. I want to add a video transmitter that is built for 12v. I plan to use this regulator to supply the 12v. ...
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3answers
70 views

Looking to use an Op-Amp to scale a high-voltage system to a low voltage system

I am looking to scale a voltage of range 30V-120V to a 9V-14V range. I am looking into using an Op-Amp and have found that ideal Op-Amps use a system that cannot take a varying 3rd input as a constant ...
1
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1answer
64 views

Microcontroller circuit

I am using a Stellaris EK-LM4F120XL for a project. The project includes an LCD module, servo motor, ultrasonic ranger and a numpad. The LCD, servo and ranger are rated at 5V operating voltage, and the ...
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4answers
97 views

LM317, basic voltage regulator, why does it get hot when not connected?

I have built this little voltage regulator circuit: circuit diagram I am a hobbyist, so these may well be screamingly obvious questions. I ask because I haven't found the answer to my first question. ...
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2answers
89 views

7809 Linear Voltage Regulator Outputs in Series

I'm building a linear power supply that converts 120VAC mains voltage into multiple 9VDC, isolated outputs. I'm using this transformer that has the proper primary winding and 8 secondaries that I'll ...
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2answers
292 views

Is this an opamp voltage regulator?

I'm trying to understand the attached schematic, which I came across when repairing an oscilloscope. Am I right in thinking that this circuit is regulating VCC (5V) down to 3.3 and 2.5 volts? Why ...
5
votes
1answer
278 views

Zener diode circuit

When I tried to find current flowing through 1.2k ohm resistor, I am finding 8.33 mA but there comes the problem: I am finding the current through the 1k ohm resistor is 6 mA. What am I doing wrong? ...
0
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1answer
60 views

Capacitors vs buck/boost converters

I'm trying to drive high power LEDs with a laptop power supply, and wondered if I should use resistors to limit the extra current, or something like this to limit the current. If I did use that ...
2
votes
1answer
109 views

Boost regulator: Unexpected output voltage

I just finished setting up an LM2577 as a boost converter, and have run into some unexpected issues. For starters, here is the recommended "typical application circuit": My application circuit is ...
1
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1answer
83 views

Stable voltage at high current

I am working on robotics project. The drive chassis is powered by a 3-cell 12V 8 Amps battery (I might also go for connecting two batteries to attain speed as my drive motors work at 24V full power). ...
0
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1answer
59 views

Voltage regulator

I have a few RC planes and I want to use them upgrade them for night flying. I would like to add EL Wire and/or Arduino + NeoPixels. I am more of a software guy than an electrical engineer so I am ...
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4answers
53 views

Voltage regulator (LM350) gives no current

I am trying to use a Fairchild LM350 to get 8 volt output. I am using basic circuit (page 5 of datasheet) to do that. I get the voltage I want but whenever I try to measure the current (by putting the ...
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2answers
80 views

Calculating the Resistor's Power Rating

I'm designing a couple of step-down voltage regulators based on a LM22677 chip (datasheet) and following the example: I want to get 5V and 10V from a 12V supply, but I have concerns regarding the ...
0
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1answer
40 views

Voltage Regulation: Cascading vs. Individual

Consider my design: Input power is either 8.4V (VBAT) or 15V (Wall Wart). From there I need several voltages to power all the components on that board. Here is a list of voltages: 5, 3.3, 2.5, 1.85, ...
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2answers
85 views

Low noise voltage regulation

I have a circuit which currently runs off of either a 12VDC wall wart adapter, or it falls back to a 9V battery if the wall wart adapter is not connected. My circuit currently uses a chip which ...
1
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1answer
62 views

Schottky power diode replacement

I'm trying to implement a 12V to 5V step down voltage regulator with a Texas Instruments LM22677, as suggested in the device datasheet (Pag 12, Fig 20). Regarding the selection of the power diode, TI ...
0
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1answer
119 views

Dual power supply: two secondaries or series regulators?

I am going to create a simple dual voltage power supply for powering logic (5V) and some stepper motors (12V). What would be a better solution: Would it be to use a transformer with two secondaries ...
0
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2answers
55 views

Best way to step down (half) battery voltage for motors

I have a 4S LIPO battery 5800mAH at 14.8V and I want to use it to power some 7.2V motors I have. The Rover 5 Chassis to be exact (https://www.sparkfun.com/products/10336), the only problem I have is ...
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votes
1answer
79 views

Linear regulator (L7805CV) outputting 5.8V

I am having a pretty strange problem that I am unable to solve. Basically, I am using an L7805CV and it is outputting at 5.8V instead of the specified voltage range in the data sheet. At first I was ...
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2answers
111 views

Voltage regulating

My first post here, please keep in mind that I hardly know anything about electrical engineering so please keep any replies in layman terms, thank you! I bought this 30cm white LED strip. It's set ...
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3answers
95 views

Truck 24V->12V DC regulator gets me 13.5 volts, how can I get it to 12.0 +- 0.5?

I am wondering whether I need a new regulator or is there something that can fix my issue. BTW, what's the deal with 24->12V regulators that all output 13.5V volts? I have quite sensitive IT ...
1
vote
1answer
94 views

How to switch power supply between two sensors

I have two ultrasonic sensors, when one sensor acts as a transmitter other acts a receiver and vice-versa. How can I supply power for the 1st sensor for 20 microseconds and switch the power source ...
0
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5answers
183 views

How to throttle power consumption of a heating coil?

Which is an appropriate but simple electrical circuit to reduce the energy (power) consumed by a heating coil which has an AC feeding without generating an asymmetric load (large DC component, e.g. ...
0
votes
1answer
115 views

How to make power supply to 434MHz receiver module more stable on RC car?

Following the recommendations I got on my last question about troubleshooting communications in my RC car, I probed the +5V power pin of my RF 434MHz receiver module with my oscilloscope. Below is a ...
0
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1answer
34 views

difference between the LM1117-5 IC packages

I'm using LM1117-5 as a voltage regulator. In the datasheet of it they have mentioned different packages like LM1117DT-5.0/NOPB,LM1117DTX-5.0/NOPB,LM1117IDT-5.0/NOPB, LM1117IDTX-5.0/NOPB , ...
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3answers
109 views

Last resort debug: Voltage limiter

Note: This is a followup to a previous question that was left unanswered. The circuit has been remade on a breadboard and the symptoms are different I have been trying to make a voltage limiter ...
1
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4answers
230 views

Can I run 12v car fan on 8v

I am planing to upgrade the radiator fans on my car and I would like to do some modifications to reduce the noise and have them run at lower speed when a curtain temperature is reached and run at full ...
0
votes
1answer
36 views

Package/Device for a component with duplicated pins

I have a L79L05 from ST Microelectronics, which has the following pinout: I have created a symbol and package in Eagle for that component. The symbol has three pins - IN, OUT and GND, while the ...
3
votes
1answer
46 views

LT1084 as Current control Regulator

I am using LT1084 as a current control Regulator. Circuit shown below Since the transistor Q2 is controlled by a PWM pulse so output voltage of LT1084 is varying as shown below Since it is used as ...
1
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2answers
111 views

What should I do with multiple 5V to 3.3V voltage regulators?

I'm trying to put a PN532 breakout board, BLE "shield" daughterboard, and a PIC microcontroller all onto one board. The PN532 breakout board has an ADP121 (5V to 3.3V) regulator, the BLE breakout has ...
0
votes
4answers
189 views

home socket with DC voltage

I'm wondering why, in a standard house, instead of using many low power AC-DC rectifier, there isn't a big (like 12V 20~50A) AC-DC rectifier which supplies some wall socket with a DC voltage? In the ...
0
votes
1answer
84 views

How can I drop voltage from 20V to 12V at 3.5A? [duplicate]

Here's the problem: I carry around two devices, but at different power requirements - one at 20V/3.5A and the other at 12V/3.5A. I'd like to only carry around one power brick and just carry an adapter ...
2
votes
2answers
98 views

lm317 current source sense resistor

Why is sense the resistor swapped with the load resistor here and how does this circuit work? From my understanding of circuit output (node at LED anode) will be at constant 1.25V, and it will ...
0
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2answers
179 views

Most efficient way to step down 48V to 12V high amperage

What is the most efficient way to step down 48V to 12V? I have a power supply that can output 48V at 40 amps. Assuming the power supply is perfect, that gives me 1920 watts. However, I'm powering some ...
1
vote
1answer
71 views

Does AMP AC/DC adapter going through a step down increase in amps per voltages (ECIG)

The latest project I'm working on is making adapter to basically use the mains for an ecig rather than usb or an battery. For anyone whos familiar with ECIGS they basically use around 3.7-6volts. It's ...
0
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3answers
79 views

Finding a replacement voltage regulator… what do the codes mean?

So I need to replace the following voltage regulator in an old Atari as it's registering 0.5V between output and ground and 24V on the input, but it's supposed to be providing 12V on the output side ...
0
votes
0answers
59 views

Is there any risk if I use two voltage regulators in parallel to increase current capacity [duplicate]

I am working with a Pcduino Board and the board requires 2A at 5Vdc. I want to power this board via a 9 Vdc battery. The problem I have is I only have access to a 5Vdc regualtor which is TS2940CZ. The ...
0
votes
1answer
58 views

How can I regulate the voltage of a Li-ion battery with the least drop out voltage?

I have a one of these: descriptions: full charge voltage : 4.2V cut off discharge voltage : 2.75V capacity : 4000mAh size : 18650 And I want to get 3.3V from it. but the problem is I can't use ...
0
votes
4answers
108 views

Can a 5V regulator connect directly to a voltage divider to obtain a 2V output?

In my circuit, a lm78l05 is used to provide +5V voltage to other parts. And now I need another +2V source to shift my input signal from +-2V to 0~4V as the ADC ad7682 limits the input signal range ...
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votes
1answer
80 views

Which caps to use for 7812 Regulator and how many?

I'm new to electronics and want to build a simple led circuit. I want to get DC 12V 1A, for the circuit, from AC. I have already bought a regulator which is LM7812> What if I use 1000uF on the input ...
0
votes
1answer
117 views

Powering circuit and Arduino with single power source

I am trying to power an Arduino Uno as well as my circuit using Li-Ion batteries. They are 2 18650 Lithium Ion batteries (rated at 3.4 V each = 7.4 V total). I have this battery plugged into the Vin ...
0
votes
2answers
87 views

Voltage limiter is shutting down completely when tripped

What the circuit is designed to do The following circuit is designed to accept a rectified (low frequency) sinewave input of amplitude 0-30V, and filter it through charging a capacitor until its ...
0
votes
1answer
100 views

External battery for laptop with 18650

I would like to try to make an external battery for my laptop. I opted for 18650 batteries. (but feel free to tell me if there are better batteries for that). I read this answer to a question here: ...