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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Powering a device through GPIO

I have a custom PCB based on imx28 (primary board). It receives external power via a cable. There is another PCB (secondary board) connected via GPIO to the primary board. The secondary board doesn't ...
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2answers
72 views

In an op-amp, what does connecting the negative supply to the feedback do?

I'm trying to understand how the LM317 works? I've found that a good simplification is the following: So a practical example would be simulate this circuit – Schematic created using ...
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2answers
60 views

Variac is blowing fuses

I'm using a variac to control voltage on a heating element and we're having issues with the fuse blowing. The variac is rated for a 10 amp fuse and we're using a 8 amp one. The 8 was suggested to ...
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1answer
41 views

Controlling Voltage

I'm seeking help in finding a way to control the incoming voltage for custom LED fixtures. My fixtures use 12V 3014 240/M LED strips with 221 resistors. The strips are wired in a parallel circuit ...
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1answer
48 views

i want to make circuit to drop voltage 24v input to 10v output by using resister [on hold]

i want to make circuit to drop voltage 24v input to 10v output by using resister By the help of pot meter.
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2answers
60 views

How to change speed of dc motor using potentiometer?

I want to change the speed of a DC motor(12V,2000RPM) using a pot and operate a table fan(where I've replaced its AC motor with DC).Now the problem is I get a regulated output at o/p of 7812 but not ...
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1answer
63 views

12V regulator for 100W LED

I want to make a 100W high power LED headlight for bike, but the problem is that LED releases a lot of heat, and I'm using a 150W boost converter to convert 12V to 30V ( minimum operating voltage of ...
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1answer
40 views

Need help finding a replacement regulator [closed]

Im trying to find a replacement for the low dropout voltage regulator shown in the pic, im located in the U.S.(Florida). All help appreciated.
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1answer
42 views

Better to regulate voltage by supplying or subtracting base current to BJT pass transistor?

As a learning exercise, I'm designing new guts for one of my venerable HP 721A (circa 1959) DC bench power supplies. With help from members of this site I was able to vastly improve the reference ...
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2answers
38 views

Voltage regulator current consmption

Our pcb current consumption is less than 0.5mA . We use a 3.7v lithium battery, and the battery goes through voltage regulator ...
0
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1answer
49 views

3.3V Voltage Regulator for LiPol battery [closed]

I'm looking for a low drop voltage regulator to use in a 600mA – 1000mA (peak) 3.3v system that can be powered either through a singe-cell LiPol battery or USB (so a max drop of ~0.4V). So far the ...
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2answers
45 views

would using the reference voltage of an ADC as a VOLTAGE SOURCE affect my ADC or the stability of the circuit?

I am using an Arduino to capture an AC signal. However, the application is sensitive and needs a high resolution, I decided to use the internal 1.1 Volt as a voltage reference for the ADC. In the ...
3
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2answers
544 views

Will the lower frequency of 50Hz AC affect overall charging time? [closed]

I'm using a voltage converter to go from 220V to 110V to charge a small appliance. The recommended charging time is 6-8 hours. However, this is specified for US AC voltage 110V@60Hz, whereas the ...
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1answer
27 views

LT3029 regulator for arduino mega

Does the LT3029 regulator give out 9v 500mA without external circuitry needed for it?... I'm planning to use it for my arduino mega... I really haven't used that regulator before ...My main power ...
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1answer
42 views

Reduce voltage after AC-DC rectification before step-down

I have a Weller Magnstat soldering station providing 24V AC to the tip. I want to use that output to power a 12V fan to disperse or absorb the fumes. With a cheap multimeter I measured 25V AC during ...
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5answers
832 views

Is there any advantage to biasing a transistor with a zener diode rather than a (resistor-based) voltage divider?

In the figures below, we see two methods of biasing a bipolar transistor: the first uses a voltage divider, and the second employs a zener diode regulator. Since the voltage regulator appears far ...
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2answers
63 views

Will AVR stabilize the flow of current? [closed]

In our village, the power supply is unstable. Sometimes it goes weak, sometimes not. You can tell it by our bulbs, it goes dimmer when the power is weak. Our monitor now shows some green and red wires ...
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1answer
34 views

TSP65070 and OMAP 1V8 pull up to 2.7V

I want to use the TPS65070, the power solution for DSP to power the OMAP L138, but i read in the errata sheet of the OMAP L138 OMAP L138 Errata page 25 that the 1V8 power supply can pull up to 2.7V ...
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1answer
24 views

Can I use an electrolytic capacitor with a MCP1826S voltage regulator?

I have a MCP1826S and according to the datasheet, I should use an output capacitor of 1-10uF and with an ESR of lower than 1Ω. I have some 4.7uF electrolytic capacitors, but I think they have an ESR ...
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0answers
40 views

reducing voltage for an external battery pack.

I'm trying to build an external battery pack for a cannon camcorder from NIMH rechargeable D cells. I need to reduce voltage by 1.07 and keep constant voltage. I'm connecting through the charging ...
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2answers
80 views

Increase LDO current with PNP

I have seen this circuit a few times. It takes a common 3 pin LDO, and adds a PNP transistor between VIN and VOUT, to increase the amount of current it can provide at the regulated voltage. It is ...
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3answers
78 views

Help with understanding strange capacitor configuration arrangement

I am on a chapter of my electronics beginner’s book where the author talks about the PICAXE microcontroller. One of the first things the author mentions in this chapter is to make sure that the PICAXE ...
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1answer
107 views

Design an E-switch

I'm trying to run a OLED display densitron with a ssd1322 controller. It requires basically two supply voltages 15V VCC supply and maximum 3.5V Vci supply voltage for operation and IO pins. There is a ...
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1answer
46 views

Connecting the voltage sense screws of a power supply (wire gauge to use?)

Very often I see high wire gauges (i.e., very thin cables) used for the wires that connect a test circuit's voltage input terminals to the sense screws of a power supply. I would have thought that you ...
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1answer
56 views

Negative supply from LM3940

I got a bunch of LM3940 to convert 5V to 3.3V. I wanted to use the same to make -3.3 V so I switched the ground and output. In the schematic the top circuit works fine and I get 3.3V out. I expect ...
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3answers
129 views

Any clever way to provide 3.3V with good current output from a 9V battery?

I'm sorry for any English mistakes as I'm not used with using it when talking about technical stuff. I have been using some ESP8266 WiFi modules with Arduino Mega for a project. They work with 3.3V ...
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1answer
66 views

Should I use a regulator to improve efficiency or safety

I am considering a low power design where I do not use a regulator. The components will operate from 1.9 to 3.7 Volts. The design is powered from two primary cells(Nominal Voltage: 1.5 Volts ...
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5answers
148 views

how to provide light for multiple 12 v led lights for 2 weeks

I'm participating in an art show soon in which I am making "sculptural light paintings" of which require a few 12v LED strips. They're the kind that work in aquariums and car's taillights and whatnot, ...
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3answers
210 views

2N3055 Power Supply

Could someone explain how this circuit works and how the output is maintained at 12V? There is very little information on how the circuit works online. I know the 12V output from the 7812 is used ...
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2answers
127 views

What does each of the basic crowbar circuit's components do?

I have a general question about the key components of basic crowbar circuit below I want to use a crowbar circuit for several DC to DC LM78xx linear regulators (various outputs, 7805 7809 etc.) to ...
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0answers
53 views

broken regulator pins

A nooby question: I installed new LDO regulators on the power supply section of a PCB, and one of the pins severed when I bent it down to screw on to the board (two of the others did not sever but ...
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1answer
57 views

12v-4.2v power supply design?

I have a Sony A7R camera and i want to make a power supply that runs of a 12v lead acid and has a output of 4.2v so i can take long time lapses, i don't know much about electronics so i came here to ...
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1answer
56 views

Build a solar panel nimh charger

Today I found this tutorial on how to build a battery/solar power supply for an arduino here. The tutorial explains on how to use NIMH or Lithium-Ion batteries for this. Step 4 explains how to use ...
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1answer
72 views

What will happen when I draw too much current from a voltage regulator? [closed]

Let's say that I have a 5V, 150mA rated LDO whose input is connected to ideal voltage source with infinite amount of current drive capability. Just to make the matter simple, what will happen if I ...
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3answers
47 views

How to work with the MCP1702? [closed]

I'm reading the MCP1702 datasheet and there's the typical circuit on page 2 depicting a 9V source and a 3.3V 50mA output. My question is: How come the current output is 50mA when the spec says that ...
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0answers
47 views

Adding a regulating circuit to supply 3.3v

Background I wish to power my circuit with a 18680 battery. My circuit actually has two parts: 1) a 18650 charger and power booster for USB at 5V, and 2) a Bluetooth LE module (running at 3.3v with ...
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2answers
110 views

Powering microcontroller by bypassing ldo regulator

I'm working on a circuit design with a microcontroller that runs on 3.3V. I'd like to be able to power it either through a 3.3v supply or a USB port. I'm using an ...
0
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1answer
60 views

19.5V to 15V - what's the best way to lower the voltage?

The problem is: I've got a power supply capable of outputting 19.5V 4A. I need to lower the voltage to power up a laptop that requires 15V and 2A. Which way is the best to do it? Construct a voltage ...
0
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1answer
45 views

Avoid heating with high current

I am new to electronics and just tinkering with it first time. I have laptop charger with 19V/3.42A and connected to 12v regulator and 3.3v regulator to get two voltages - 12v and 3.3v. I am going to ...
0
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1answer
25 views

Large voltage/amperage battery issues

I have purchased this lithium polymer battery (11.1V, 5500mAh), to power a robotics project. The project uses a Raspberry Pi, three continuous-rotation servo motors, a couple of LEDs and a Sparkfun ...
0
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1answer
130 views

dropping 24v to 12v simply and efficiently

I have a 24v solar system, and I want to get only 12v from the DC output Currently I am taking a wire from only 1 battery, but this causes unbalance in the batteries and I have to check it a lot and ...
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2answers
74 views

LD1117V33C Voltage Regulator only producing 3.28V

I have a LD1117V33C Voltage Regulator connected to the output of a 5V regulator (LM7805). There is a 100uF cap across input (9V) and a 10uF cap across the 5V. I'm expecting 3.3V from the regulator but ...
2
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2answers
157 views

How does this slow turn-on regulator work?

I understand R1 & R2 are for feedback which the regulator uses to set output voltage. What is the purpose of the 50k ohm resistor, BJT, and the lower 10uF cap? Does the capacitor & resistor ...
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0answers
44 views

Handmade usb charger

I am a mechanical engineer and I don't have so many knowledge on electronics. I tried to make a solar charger . I had a 12v12ah battery,a solar panel 20w, a battery charger and a dc-dc converter ...
0
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1answer
53 views

Common-Drain Amplifer vs OP-Amp for unity gain (voltage Follower)

What is the difference between using a nFET vs OP-Amp as a unity gain amplifier, i.e. voltage follower. Application: Provide constant voltage with a variable load, see example below: Min Current ...
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1answer
63 views

Boost converter with 2A load

I'm trying to put together a boost converter to take a 11-14.4v input and boost it to ~17v with a max current of 2A. Most of my designs (made either by calculations done by me or a calculator tool ...
2
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2answers
57 views

Safety/efficiency of a makeshift aluminium can heatsink?

I had recently received a 9v 1A DC wall-wart off eBay, and needed to open it to swap the polarity of the jack to center negative. As I had the case open, my finger bumped against the metal part of the ...
0
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1answer
54 views

Buck converter charge battery control output voltage

I have a buck converter charging 8 series of Li-Ion batteries ( 8 x 4.2 voltage of charging) with a source of 36 V. I am using this schematic (from here): I know that for a resistive load, the ...
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1answer
88 views

PNP or NPN Transistor for this schematic?

I am quite new to electronics and hoping to build a voltage regulator using the schematic below. I will be using a 7806 regulator and a 7.4 Lipo battery (yes, the schematic is probably a little ...
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2answers
79 views

Regulate water flow from a water pump [closed]

I have an aquarium water pump of following spec: Voltage : 220V-240V (AC) Watts : 20W ...