Questions tagged [3.3v]

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656 views

LM1117-3,3 keeps using more and more current

In the process of fault finding a circuit I am building using an ESP8266, I think I found the problem may be with my LM1117-3,3. The circuit starts off fine drawing between 80 (off state) and 160 (on ...
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1answer
3k views

ULN2803 - do i need COM(VSUP) for relays ?

I'm building a relay board with SRD-03VDC-SL-C relays and an ULN2803 Darlington transistor array. As I am a beginner I don't understand the purpose of the COM pin? In the datasheet VSUP (Coil Supply ...
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1answer
3k views

Powering 3.3V I2C from Arduino 5V?

I need my Arduino to communicate with a fairly sensitive 3.3V I2C device, and am using a Bidirectional Level Converter to step down the voltage. However, I still need a 3.3V source (for the I2C ...
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2answers
3k views

High-side switching 12V with BJT/MOSFET

I think I got too ambitious with an earlier post, so lets back it up a bit. I would like to use a 3.3V output from a Raspberry Pi to high-side switch a 12v load. I thought this was possible with a ...
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1answer
1k views

What do you call a 1:3 turn ratio transformer?

I need a small surface mount or slightly larger transformer with a 1:3 turn ratio that will triple my voltage from 3.3 to 9.9 volts. I have been literally searching the internet for such a thing and ...
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2answers
338 views

Logic family for 3.3 V microcontroller interface

I need to generate a bunch of chip selects for a SPI bus that I want to use on a project. I will use a 36 position (similar to PCIExpress = cheap) card edge connector and etc. The bus is simple : <...
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2answers
646 views

Connecting the Beaglebone Black to the KK Mini flight controller

The flight controller needs to be sent 4 PWM signals at greater than or equal to 5 volts. Since the Beaglebone Black(BBB) GPIOs can supply only 3.3V I needed to change the signal from a 3.3 volt one ...
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2answers
79 views

Help with Texas Instruments SN74LVT125

I am interfacing a 5V system to a 3.3V using the SN74LVT125 to shift down TTL voltage to 3.3V My problem or my question is, Some of the input pins (the A ones) are being triggered by a 5V signal that ...
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1answer
805 views

Level shift from 5V to 3.3V (and vice versa) using 74HC4050N,652

Below you will find a link to the datasheet for 74HC4050N. My order I placed had a suffix of ",652" on that part, but I'm not sure what that number refers to. http://www.nxp.com/documents/data_sheet/...
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4answers
36k views

For 3.3V microprocessors, what's the best way to power the gate of a MOSFET?

The new processors are all 3.3V and dropping. So while I am used to 5V arduinos being able to power the gate of a MOSFET, at least most of the way, this is not going to be true any more. And for an ...
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1answer
1k views

3.3V to 5V logic converter using p-channel mosfet

I am trying to convert a 3.3V logic signal to 5V logic signal. I am using a p-channel MOSFET and I can not get it to send the full 5V signal through. Below is the circuit I am using.
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3answers
1k views

Interfacing open-collector optoisolator to 3.3V microcontroller

I have a bit of a puzzle on my hands trying to interface a Fairchild MID400 optoisolator (popular "logic level" optoisolator for mains detection) to a 3.3V GPIO pin. The MID400 is a 5V part [*] and ...
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3answers
2k views

voltage of input(+5V) is greater than the supply(+3.3V) provided for 74HC245 buffer

In my design I am using 74HC245 buffers between a input signal of +5v and controller pins of +3.3V. What is the supply value I have to use for buffer (74HC245). I want to use +3.3V as the supply, but ...
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1answer
180 views

Power Efficiency of Embedded system

I am designing an embedded system and I am hoping to achieve maximum power efficiency as the system will be running off of 2x CR1620 batteries. In addition to power efficiency, I would like to keep ...
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2answers
2k views

How to output 5V from 3.3V MCU?

Big picture: I want to control a LUXdrive 3023 BuckPuck LED driver (3023-D-E-1000) from a Particle Photon (essentially an ARM Cortex M3 microcontroller). The MCU runs at 3.3V. I have tried a few ...
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1answer
2k views

LM2576 12V to 5V and 3.3V

I want to step down the input voltage from my power supply (12V) to 5V and 3.3V. Please see my schematic. Is it right or wrong? I use LM2576 as switching regulator. Thanks. Sorry for noob question
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3answers
12k views

Safely pull 5V to GND on 3.3V GPIO

I want to control an 5V relay board with an ESP8266 (which operates on 3.3V). Schematic of the board: IN2 is normally on 5V and must be pulled to 0V for enabling the relay. I saw people using an NPN ...
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1answer
112 views

What is the methology of sending signals via Bi-Direcional MOSFET?

I am trying to make a simulation by using Multisum 14 for i bi-directional channel for Logic level circuit from SparkFun which use Philips AN97055 IC as a Bi-directional level shifter... My circuit ...
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1answer
1k views

What is that meaning of “This Sensor uses 5v as a working Voltage only”?

I am trying to understand the meaning of a 3.3v or 5v IC but I don't know how to use the right keyword in search engine to find the explaining article so I'll explain... We know Arduino UNO R3 as ...
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3answers
87k views

How do I use a 5V relay with a 3.3V arduino pro mini?

I'm using a couple arduino pro mini's (3.3V) for a home automation project and want to add relays to the final PCB design to switch some stuff on and off. Since I want to use a 5V relay like this: HF ...
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4answers
5k views

How can I turn off a 3.3V circuit with a 3.3V microcontroller

I'm working with ATTiny85 that has low current (40 mA) GPIO. In the other side I have a power supply (battery with ~5V) connected to a LM317 and an ESP8266 that demands high current (more than the ...
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2answers
827 views

AMS 1117 -3.3v Protection

I'm using AMS1117 -3.3v regulator for providing 3.3v to my IO expander mcp23017, unfortunately some short circuit happened and my regulator gave 12v to IO expander, which burned my IC. How can i ...
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1answer
445 views

Connecting Sharp GP2Y1010AU0 (5V) to ESP8266 (3.3V) - pin nr 3 - do I need transistor?

I'm connecting Sharp GP2Y1010AU0 to WiFi module ESP8266. Sharp GP2Y1010AU0 is powered by 5V and ESP8266 by 3.3V. I wonder if I need a transistor between Sharp's pin nr 3 and ESP8266? If yes, can it ...
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3answers
7k views

Newbie : Overheat LD1117 3.3V Regulator (Input Voltage 5V-2A)

I am trying to get a 3.3V voltage from 5V (2A) power supply to power my Arduino Pro Mini 3.3V. I am using LD1117 3.3V Regulator (TO-220). I haven't connected any coupling capacitor as the datasheet ...
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2answers
4k views

3.3V from 5V Voltage regulator

I wish to build and get 3.3V from LM7805 voltage regulator with some extra parts like resistor and maybe a zener diode. How can I achieve that, is it even possible to do that?
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2answers
1k views

Driving a 24V isolated load from a 3.3V MCU

I am looking to drive a 12-24V purely resistive load from a 3.3V MCU. I would like to use an opto-isolator to separate the circuits electrically. I've drawn up the following circuit, but I'm not ...
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1answer
100 views

Logic level issue

I'm new to electronics so please be patient with my ignorance. I'm currently dealing with a problem where my primary device deals with 3V logic (Esp8266). The output from my second device when on ...
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1answer
94 views

The best use of battery power

My project involves a number of components. Some are 3.3v and some are 5v The project must be powered by 8 AA batteries. Most of the time the components will be in a low power state. But they will ...
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1answer
106 views

MCP1755S regulator and output voltage

With a homemade PCB, I've built my own Arduino-inspired controller, with an ATmega328P flashed in a way to work @3.3 V. I power the whole thing with a battery@ 7.4 V. I use the LDO MCP1755S ...
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1answer
10k views

which is better? 5V or 3.3V as the supply voltage

I am about to design a new microcontroller based project. I checked all components (few) and all can operate at 3.3V or 5V. the microcontroller itself can also operate at 3.3V or 5V (pic micro at only ...
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2answers
8k views

How to get 3.3V from 2 AA batteries? [duplicate]

I would like to know if its possible to 'step up' the voltage from two AA batteries (3V for Alkaline and 2.4V for NiMH) to a stable 3.3V ? I need to find a good power source for a circuit that I'm ...
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4answers
31k views

How to get 3.3 output voltage in PC817 opto coupler?

I am using PC817 opto coupler. I want a 3.3 output voltage. In its 1st pin I am giving 12volt and 2nd pin is gnd. I have connected a pull down resistor on 3rd pin. ...
7
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3answers
22k 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 ...
7
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1answer
13k views

MOSFET choice for 12v LED Strip and 3.3v Logic

I'm currently planning a project on a low-cost WiFi-enabled RGB LED controller and could use some help in looking over my parts list and general concept. What I'm wanting to do is a build a ...
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2answers
6k views

LD1117 not providing fixed 3.3V

It is my first question on this site and I'm probably doing something wrong, try to be gentle! haha I want to provide 3.3V to my ESP8266 module from my Arduino, but people say this WiFi module ...
0
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1answer
107 views

SPBT2632C2A Operating Voltage Related

Is the SPBT2632C2A compatible with a 3.3v Logic System? I was thinking of using it with a BeagleBoneBlack, Absolute maximum rating is rated for 5.5v, So i can feed the module power from a LM1117-3.3 ...
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1answer
6k views

7-segment blue LED display at 3.3V

I'm driving a blue 7-segment LED display with a TI CD4026BE on a 3.3V circuit. I cannot find any data sheet for the display part. It has a common cathode pin layout and it's marked FJ5161AB on the ...
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4answers
6k views

Can I program a 3.3V ATmega MCU with 5V programmer (USBasp)?

short question: I have ATMega8A at 3.3V I have USBasp programmer at 5V (from USB port) Can I program this AVR with this programmer directly? Well, ATMega can stand 5V but it's powered with 3.3V so I ...
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2answers
342 views

Using AA(A) batteries to power a 3.3V SoC

I have a 3.3V SoC that could draw up to around 250mA - 300mA. Is it a good idea to power it using 2x AA(A) batteries? Is it supposed to be an unstable setup without decoupling capacitors? Thanks
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1answer
1k views

Convert FT232RL board from 5V to 3.3V

I have a couple of these FT232RL breakout boards direct from China, look like they are Folger boards. I measured the voltage between Vcc and GND, and it's 5V from the factory. It has 3.3V pad on the ...
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2answers
5k views

drive a relay from a 3.3v 2mA max output

I need to drive a relay, but my logic signal is limited to 3.3v with a maximum of only 2 mA. Can I use a level shifter? I have a 5V relay with a 125 ohm coil drawing approximately 40 mA. Any other ...
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1answer
1k views

How do I troubleshoot this high-frequency PWM fan control circuit?

I have a 230 Volts fan from EBM papst. It is a fan that can be controlled through a PWM signal (between 1 and 10 kHz). I have built the circuit that is in the manual (see image) I did get this ...
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2answers
937 views

Wide input voltage range buck converter/circuit to 3.3V 150mA

I am building an appliance that should work in very wide range input voltage: In some scenarios input is 5VAC, in other scenarios it can be 250VAC. It's not a problem to convert AC to DC, then ...
1
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1answer
916 views

Designing power supply with 5v and 3.3v from a 12v supply with switching regulators

I have 12V DC coming in from a power brick and I need to supply 5V @ 1A for USB and 3.3V @ 5A max for mSata and PCIe. I basically need to make a small atx power supply that I can integrate on my ...
1
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1answer
383 views

Pololu step-up converter drops voltage

I have a Pololu 3.3V step-up converter - U1V11F3. I tested it by connecting a regular 1.5V alkaline battery for input and a resistor at output. With no load or small load (10K) it keeps the output ...
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1answer
2k views

Can I run an ATmega on 3.3V with an external 16 MHz crystal? [duplicate]

I have been told that is overclocking or it just will not work, but I want to be sure. And are there any real differences that would effect from this? Any tips and tricks will help, thanks!
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1answer
1k views

Atmega328 to SD card issues [duplicate]

I am working on a board that includes an Atmega328 which needs to read data from an SD card. I am having problems. Here is a diagram: I believe the issue may stem from the voltage divider that is ...
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2answers
1k views

Solid state relay (or equivalent/alternative) to drive 6V DC from a 3.3V micro

I have to open/close two wire from a closed device. I cannot open due to it's under warranty, and the only part that I can open and modify is an external button that connects the two wires. Firstly I ...
3
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2answers
614 views

Interfacing tri-state logic across 3v3/5v. Do buffers mirror all three logic states?

(This is just learning/hobby stuff...) I have a 5v (tri-state TTL, ZX Spectrum) bus and I want to interface some non-5v tolerant 3v3 chips to it. I think I need buffers or transceivers for the level ...
0
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1answer
589 views

3v Relay raspberry

I'm trying to drive a 3v Relay with a schematic like this: Relay is a HWE JRC-21F and transistor is a PN2222A instead of a BC337. This won't work unless I connect 3.3v directly to transistor base, ...