# 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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### Help Needed with Voltage Controlled Synth Circuit

I am building a somewhat out-of-the-ordinary guitar pedal that involves some synth elements, namely controlled voltage. I'm a little confused by something that I suspect is actually pretty basic. I ...
2answers
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### How to use negative voltage feedback to make output voltage constant?

I have the circuit below, which generates 1.5kV from a transformer. The primary is driven by a MCU oscillator, mosfet driver and a pair of n-channel mosfets. It works very well as it is: But now I ...
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### Drive voltage regulator Vout when Vin is floating

I'm designing a system that can be powered both at 12V and 5V. The circuit works at 5V, so a voltage regulator is used when the power is at 12V. A jumper (or several jumpers, given your answers) will ...
1answer
50 views

### LM317 vs series diode (1N4007) as voltage regulator?

I am using the SIM900A GSM module which requires 3.2V to 4.8V with max current draw of 2A. In my board, I have a 5V, 3A supply which will be used to power the SIM900A. Generally, in my search I ...
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118 views

### LD1117v33 to get 3.3v

I am using ld1117v33 with Vin as 4.97v and trying to get Vout as 3.3v. I am actually getting this Vout without using any capacitors or resistors. The datasheet has suggested to use two capacitors, 0....
1answer
49 views

### creating a basic voltage regulator [on hold]

How do I create a simple voltage regulator for a 120V input voltage. The voltage regulator basically need to send an output of 25%, 50% and 75% of the input. Can this be done by simply using a bunch ...
2answers
74 views

### What happens if the input voltage of a low dropout regulator is under the rated minimum voltage? [duplicate]

I am not that familiar with regulators, so, I want to know what happens if the input voltage is under the rated minimum voltage? Does it give zero volts or something under the rated voltage? If it's ...
2answers
45 views

### Voltage regulator minimum input voltage

I have a L78S05V voltage regulator (5V output). The datasheet's maximum ratings suggest the maximum input voltage (35V). I would like to know, is there a minimum input voltage? I have a circuit that ...
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### 1-2kW solar voltage regulator cca 28.9V to 24V DC stable [closed]

I've got several solar panels simillar to these http://www.solardesigntool.com/components/module-panel-solar/BP/984/BP3220T/specification-data-sheet.html Each panel is rated 28.9V 7.26A (max 210W) ...
3answers
57 views

### Negative Voltage Reference For Instrumentation Amplifer

I'm trying to measure a variable resistance, RX, creating an AC voltage with two PWM and applying it to a wheatstone bridge. The PWM goes from 0 to 3.3v and to measure the voltage differential i'm ...
0answers
45 views

### Can't find Step-Down VREG in D2PAK with “strange” pinout

I'm repairing a device. I have found burned VREG. Seems like simple adjustable step-down voltage regulator with integrated switch in 5-pin D2PAK/TO-263. IC package was damaged and label isn't ...
1answer
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### Mini Workbench Adjustable Power Supply

I'm trying to design a mini workbench power supply to use for small electronics that is powered from the 12V rail of an old ATX power supply. I want it to be able to provide an adjustable voltage of ...
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### Providing 5V from 12V battery with minimal energy loss

I notice that in switching power supplies for computers the final stage, where they convert, say 16V to 5V, often just a resistor is used to draw down the voltage. So, they are dumping 12V, which I ...
1answer
78 views

### Is this an appropriate way to test a 7805?

Trying to check some 7805 voltage regulators. I do not have a DC power supply and do not want to test with the circuit hooked up to mains. That leaves me and my multi-meter. http://www.androiderode....
2answers
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### Stepping up voltage from solar for a power brick (5V to 15V) possible?

i have a 28mAh power brick capable of charging my laptop when charged. I bought a 28W solar panel which outputs 5V over usb capable of charging ipads etc, however when i connected it to power brick's ...
1answer
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### Need help with LM317 voltage regulator circuit

I am new to electronics and not quite sure how to debug a circuit. I created a simple regulated power supply circuit as following using LM317 voltage regulator. simulate this circuit – ...
1answer
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### LM317 Maida Style regulator

I need to build a regulated 48VDC ~1amp power supply. I have two transformers on hand: One with a 36VAC secondary which would give around 51 volts DC once rectified The other with a 44VAC ...
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74 views

### Regulating voltage at end of 200 foot 120 V AC extension cable [migrated]

I am needing to drill some anchor bolts into concrete using an electric Hammer Drill (Electrical Rating 120VAC / 60Hz / 10A). I am working in a warehouse, and the worst case scenario, the furthest ...
1answer
48 views

### Voltage Regulator drawing 0.5A with no load connected

I recently bought an AUK S1117-33PI 3.3V voltage regulator. Unfortunately, I don't have a proper bench top power supply, so i used a basic travel adapter ,whose output is 5V - 1A, just to test the ...
1answer
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### Linear Regulator: Output current for stabilization different than datasheet?

TLDR; Why does my regulator require a minimum current for stabilization if the datasheet specs 0 mA as the minimum output current? I have a strange situation that I've "found a solution to," however ...
0answers
50 views

### An SoC pulling the power source voltage

I'm trying to power a SoC with a battery as in the figure below. The SoC in question is the WeMos, based on the ESP-8226. simulate this circuit – Schematic created using CircuitLab When ...
1answer
78 views

### How to power ESP8266 from changing voltage

So I'm very new to electronics of all sorts, have done some basic repairs but I'm interested in learning more. The project I have in mind is to use the cheap and easily available Doit NodeMcu Lua ...
0answers
47 views

### Why does my SEPIC converter output more power at higher temperatures? What are the implications of this behavior?

I have a Pololu S18V20ALV SEPIC voltage regulator board that is wired to a high-amperage 5V USB power source on the input and a DC brushless fan on the output. The output is set to about 5.5V. ...
1answer
58 views

### 24V AC converter to 12V DC at 1.2A

I am facing annoying troubles converting 24V AC to 12 V DC. The goal is to supply 1.2A current to 12V DC load. I am both limited in input power (I can only use 24V AC output of a transformer that can ...
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58 views

### Can I power two linear DC regulators, each running a motor, from a single 12v source?

simulate this circuit – Schematic created using CircuitLab I am building a twin air pump for a pond, powered by a 50W PV system with charge controller connected to a DIY fused DC consumer unit. ...
2answers
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### 24 VDC source to 0-5 VDC or 4-20 mA manual input

I have a PLC which offers analog inputs of either 0-5 VDC (6 VDC max) or 4-20 mA (sink). The source will be 24 VDC and I want the input to be manually adjustable (assuming with a potentiometer). The ...
1answer
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### Battery Charger From DC Motor

So long story short I'm attempting to build a charger for batteries using a DC motor. The batteries I'm planning on charging are old smartphone batteries at 3.7V and 1000mAh. The DC motor that I am ...
2answers
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### GoPro Hero 2 Battery Elliminator? (3.7v versus 5v)

I have an old GoPro Hero 2 who's external USB plug has failed, and I have no way of powering it externally. I need to run this GoPro using an external wired power source (available over a 5v USB). ...
2answers
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### Picking a voltage regulator for 12V/10A input -> 3V/290mA output

Am I doing the correctly? ATSAMD21G17A-AU p.906 - ARM-Based Microcontroller - 7mA MAX-7Q-0 p.16 - GNSS module (GPS) - 67mA LPS25H P.8 - Barometer - 25uA Si7013-A20-IM1 p.4 - Temperature - 180uA ...
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### A problem with Pololu S7V8A

I recently bought a voltage regulator from Pololu in order to connect my ESP8266 which requires a stable voltage of 3.3V to a LiPo battery with voltage between 4.20 and 3.7V. Now I am trying to set up ...
4answers
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### Using voltage divider in a circuit

I am designing a circuit for SIM900 and PIC MCU. I am facing few problem on power supply for them. I will be giving 12v to the ...
3answers
101 views

### Easy 9-12Vdc to 6.3Vdc/300mA circuit?

i'm in need to reduce the 9 to 12V from my power supply to 6.3V, for a current consumption of 300mA. Here's the requirements: Cant be a switching solution (so Buck converters are not an option) ...
2answers
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### How to calculate Voltage and Current?

I recently purchased a S111733PI Voltage Regulator. I'm trying to step down 12VDC to 3.3VDC, however the data sheet suggests the use of R1 and R2. They can be selected once I know Vadj and Iadj, how ...
2answers
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### Odd bypassed resistor network in the representative circuit of an MC7805 - what does it do?

Another question recently asked about the MC7805, and linked to its the datasheet for the generic MC7800-series of regulators1. When I read it, I noticed Figure 1, Representative Schematic Diagram, ...
2answers
60 views

### Dual power with lm1117 5V

I am working on RGB light strips. I have created the circuit that includes at Atmega 328P processor. See attached image. I have question about applying dual power supply. If using only 5V supply, ...
1answer
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### How to choose the transistor and the resistors connected to it [duplicate]

I am using the regulator TL497 in the case of I(pk)>500mA so I need an external transistor for that but in the datasheet they don't mention how to choose the transistor and its resistors does anyone ...
1answer
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### I can't find the values of the currents

The picture below is on page 7 of the datasheet of TL497, it is a switching regulator that I use as an inverting regulator (it has an inverting mode) to generate -24V from 12V in input, in the first ...
1answer
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### What does the “Dice” package look like? [duplicate]

Looking at a datasheet of an inverting regulator, I found something peculiar: I've never heard of a Pin-Package called "Dice" before, and it doesn't even specify the pin-count. On the package ...
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### Minimum Switching Current in Boost regulator Datasheet

I am planning to use TI TLV61220 in one of my designs. My design will be in sleep most of the time & the current in sleep mode is 10-20 uA. In active mode, it wil take max 10mA. The device is ...
1answer
37 views

### Studying Behavior of an EEG Device

I have an EEG brain signal measurement device. I need to calibrate it -- i.e., I need to be able to apply known voltages to it and see its output. After doing this many times, I want to be able to ...
3answers
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### Power supply problems

I am building a +/- 45V power supply to drive a master-slave amplifier for a sonoluminescence experiment. I am following a stock design, and am having massive sag problems. The circuit powers up ...
1answer
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### Voltage regulator bypass capacitor placement

At both the input and output (especially the output), I need to place several bypass capacitors (all MLCC). The datasheet for the voltage regulator seems to suggest that using a 10uF on both the ...
0answers
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### Connecting microcontroller to battery of working mobile phone

Is it safe to use battery of working mobile (ex. Nokia 6310i) through voltage regulator as power supply for MCU? If so, is it safe to charge phone while MCU working?
1answer
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### Help with burning inductor in an LM2576 regulator [closed]

I was helping a friend to design a constant 3A current source using an LM2576 to drive a load. Problem is that the 100uH inductor keeps burning every time the circuit is switched on. One option is to ...
2answers
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### Optimizing regulator power circuit for low noise?

I am trying to understand the attached circuit. It's an ADP3333ARMZ-3.3-R7 regulator to provide 3.3V to an analog system. My goals is to have a very low noise regulator and power circuitry for a 16 ...
1answer
50 views

### Creating a simple voltage regulator for medium currents

Question, as fast as possible: Would this circuit regulate poorly-regulated +12VDC effectively? I am an electronics level zero, so please bear with me. Please let me know if you would me to clarify ...
2answers
428 views

### How do zener diodes regulate voltage? [duplicate]

So i read about the Zener diode voltage regulator circuit in the The Art of Electronics book, it made no sense to me, then I read about it in this article which was ...
1answer
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### MCP16301 Step Down Voltage Regulator PCB Layout Validation

I'm looking for some feedback/validation that the layout for this MCP16301 is correct. I'm trying to get 600mA 3.3v Out from 12 input. I'm using the circuit as described in the datasheet on page 23 ...
6answers
663 views

### Rationale for operating the diode in the (reverse biased) breakdown region

For the circuits I've studied thus far involving diodes (which admittedly are not that many), they have been nominally used in the forward-bias mode. For example, the LED only lights up when it's ...
3answers
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### Is it reliable to use Li-ion battery + LDO for analog circuits and 3.3v digital circuits?

I'm doing a project measuring ambient light with 'photodiode + op-amp + ADC + cortex-M0+.' For a while, I used stable DC source for providing 3.3v to every components. The next milestone is making ...