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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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 ...
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100 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 ...
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158 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 ...
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75 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 ...
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3answers
67 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 ...
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111 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 ...
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38 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 ...
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62 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 ...
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58 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 ...
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1answer
45 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 ...
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4answers
95 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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66 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 ...
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1answer
57 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 ...
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2answers
69 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 ...
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61 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: ...
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127 views

Linear Regulator: MOSFET vs BJT

Currently I am doing a project on a voltage regulator. Can you tell me some advantages of MOSFETs over BJT? Apart from a higher power loss, I can not find much. In control engineering it is much more ...
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75 views

How can this isolated DC/DC converter claim a 3kv rating?

I'm referring to the Murata Power Solutions CME series DC/DC converters. Datasheet: http://www.murata-ps.com/data/power/ncl/kdc_cme.pdf If you look at the footprint of package (the -3C variant), ...
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64 views

Fire pit dancing to music — increasing the voltage from a subwoofer out

I am creating a propane "regulator" which allows the user to connect a speaker output to control a valve (0-10V max:0.185A) which opens more with higher voltage. Here's a video of it operating ...
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107 views

Why is this 5V voltage regulator not outputting 5V?

I purchased a bunch of LM330T voltage regulators and in my testing, it's outputting about 5.9V when I feed it 6.5V. It's listed as a 5V regulator at Digikey: LM330T-5.0/NOPB Here's the data sheet: ...
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2answers
133 views

Reducing Ripple in the Zener Regulator

In the Art of Electronics (Horowitz & Hill) the following circuit is given as a solution to reduce ripple current caused be variations in input voltage (pg. \$ 69 \$): "An alternative method ...
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129 views

Charging 10 1.2V nicd batteries

I have 10 x 1.2V Sanyo NiCd batteries. They are connected in series. I would like to charge them. The thing is, I don't have a charger. I looked up chargers and they are all quite expensive(I live in ...
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175 views

Why would the output voltage of a 5V SMPS (USB charger) increase with load?

I've been using a USB voltage/current measurement device to evaluate power consumption of USB devices and performance of USB chargers and batteries. Most of the USB power supplies I've used are ...
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4answers
105 views

Does a “Buck Step Down Voltage Regulator” provide constant output voltage regardless of input voltage?

I've got a small solar cell panel rated at 20V on a good sunny day. I need to regulate this down to 13.8V to charge a lead battery. Can I use a "Buck Step Down Voltage Regulator" for this? I'm ...
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45 views

Linear regulator drawing power when powered from output only

I have a microcontroller circuit with a 3.3v linear regulator providing power when run by a 5v supply, the circuit can also be run directly from a 3v battery which connects to the output side of the ...
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202 views

Current boosting problem with 78xx

I've built a PCB with a 7805 based power supply on it. I tested the other parts of the PCB on a breadboard before I had the PCB made, but as the power supply circuit looked straightforward, I just ...
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34 views

Cascading LM300 series VRs?

Would it be ok or efficient to reduce a 120 volt to 44 volt transformer first down to 17 volts DC through a LM338T then again through a LM350T to output 9.5 volts DC so I can use an 4700uF 25 volt ...
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4answers
69 views

Drop 12v supply to 6v to power a water pump [duplicate]

I have a submersible water pump that requires 2.5-6V. I want to power it from a 2A, 12V supply. I assume that's powerful enough, but the pump doesn't specify its current. How can I determine the ...
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1answer
95 views

how to provide a steady voltage, in case of source voltage drop due to heavy consumers in the circuit

I am designing an arduino circuit in which the power source is a battery connected to some heavy current consumers, these consumers are intended to work for short time and infrequently, my question is ...
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1answer
34 views

PWM input voltage regulation

I have a 12V DC motor that I plan to run in one direction with PWM input at 21A. However, in the other direction I want to drop the voltage to limit the speed. Ideally. the regulator would sit between ...
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3answers
75 views

Battery current reduction [duplicate]

I have made this circuit: Now I am trying to use this circuit in my bike. My bike has a 12V 9amp battery and while charging (bike running), the voltage fluctuates from 12V to 20V. To power this ...
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Switching Regulators in Series

looking for some help regarding switching regulators for a personal robot project. The problem: I have: two 18v 4.5Ah batteries (which when fully charged are actually more like 21v) I need: 5v/1A ...
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57 views

Clamping Voltage without disturbing the power supply

I am using a circuit similar to the following, to clamp the input to my microcontroller to around 5 volts: How do I make sure that the (5V) power supply is not disturbed and stays regulated. I am ...
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51 views

Minimum voltage rating for output capacitor for use with LTC3525-5 boost voltage regulator

I'm (still) selecting parts to build a 3 to 5V boost DC-DC converter using the LTC3525-5. The board I'm planing to build is based on the typical application shown in page 11 of the aforementioned ...
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62 views

Low current (~100ma) buck voltage converter simple, low cost options (48V to 12V)

I have 48V AC-DC power supply that I use to drive high power LED drivers. I also want to use the same 48V input to power a 12V fan and Arduino Pro Mini. Fan is rated at 0.25A but I could do without ...
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69 views

Different power sources for pcb

I have a project with arduino. Most devices are powered by the arduinos 3.3V source. But a gsm modem with 5V input and high current consumption cannot be connected with the arduino, because the ...
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4answers
170 views

How to drop 240V DC to 5V DC

I would like to drop a 240V DC voltage to a 5V DC voltage to supply electronic. The 5V stage needs less than 5mA in current. The solutions I looked at are: Resistor divider (Not really ...
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2answers
75 views

What should I use for a 3.3 voltage reference that sinks maximum of 1mA?

I am in search for stable and precise 3.3 voltage reference IC. I am using it for the temperature sensor application which only sinks 1mA at max. Can someone suggest me a best component/IC for this ...
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1answer
92 views

Can DC voltage be divided?

I have got an old camera that runs on 7.2V (2 cell li-ion). I only have a 4 cell li-ion battery. Is it possible to divide the voltage without using a DC-AC converter and a transformer? I have looked ...
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1answer
68 views

Battery pack for DSLR coupler

I am planning to make a battery pack, by using rechargable batteries, that i can use to power my DC-coupler for my DSLR camera. (Ref. Image) On my original camera battery it says 7.4V 1.2A but i ...
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2answers
87 views

Finding batteries to make a stable 12 V battery-power supply

I want to make a stable 12 V battery-power supply for RPi and LED matrix. Schematic is something like: ...
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288 views

Can I obtain a new voltage source from outputs of two cascaded linear voltage regulators in practice?

I have a device which works with 7V. I have a 7812 and 7805 already running in the circuit. Can I use the outputs of this voltage regulators to feed the 7V device? I know this is possible in theory. ...
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1answer
53 views

Battery supplying different voltage

I 'm trying to build a portable device running on battery. It needs power at 2 different voltage: 3v and 4.5v Is doing something like this a good idea ? if so, what type of diode should be used ...
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1answer
129 views

Two or more different regulators connected to one battery

I want to make batteries provide power to both a micro controller (Raspberry Pi) and a 4x4 LED matrix. A simple circuit diagram is shown below. (only one LED is drawn in the fig. But regard it as LEDs ...
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1answer
66 views

What will happen on regulator as battery gets depleted?

I want to make a 5V-power source with four 1.5V-AA batteries. I think it can be done easily with 7805 regulator. What I am concerning is the case that batteries are getting depleted as time goes by. ...
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32 views

Current of a circuit with regulator

When the specification of a regulator says that output is 1A for example the whole current of the circuit will be 1A? For example I have a regulator in series with a 100Ω resistor and a 7V source.The ...
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44 views

DC regulator ground with Arduino [duplicate]

If I wanted to control several ICs that exceed the current rating of an Arduino 5V supply pin with an external DC regulator (which also would power the Arduino itself), should the ground planes of the ...
0
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1answer
59 views

Ground type for DC regulator

When considering a simple DC regulator such as a Texas' LM22677 on a PCB, should it use the digital or analog portion of the ground plane? EDIT: Contextualizing, I have a 12V input feeding two ...
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98 views

*very* Low voltage regulator

I've been shopping for a voltage regulator that works in a range of .5-1.5 (+/-.5) Volts, but they are not easily found. I'm wondering if anyone knows whether they even exist, or possibly how to make ...
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1answer
83 views

Looking for good LDO regulator

I'm looking for a LDO regulator that will output 12v and provide ~2Amps, and has a shutdown pin/low quiescent current. I've seen a few but they run 4$+ a pop, is this common for LDO's to be this ...
2
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1answer
136 views

LM7805 and Zener Diodes

I'm boosting an LM7805 to 16V using Zener diodes in series at the GND pin (pin 2) of the 7805. The Zener Diodes I'm using are 1 of each of the following: 3.3V, 3.0V, and a 4.7V. Now theoretically I ...