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Questions tagged [3.3v]

Questions regarding 3.3V level signals, level-shifting, and circuits.

0
votes
1answer
56 views

Would this switching power supply work?

I'm trying to design an integrated power supply to use in IoT projects that I'm working on, some including microcontrollers like the ESP8266 or ESP32. In previous projects I've made, power supply ...
0
votes
2answers
58 views

How can I get a loud noise out of a 15mm piezo disc?

I need to get an as loud as possible noise out of a 15mm piezo disc, using only the 3V from Arduino. I know I will have to make some sort of amplifier circuit, and I have attempted to make a basic ...
-4
votes
2answers
102 views

0-3.3V to 0-5V step by step [closed]

I have a 3.3V microcontroller. I want to use dac. I will work 0-5V range. But my microcontroller has max voltage 3.3v. I want to use a amplifier. I wait your recommendation. note: how can i this. ...
0
votes
0answers
75 views

What is the most sane way to switch between 5v and 3.3v on a PCB on the same lines?

I apologize for the blasphemy I may spit during this question, I am a newbie in electronics. That said, I want to design a PCB that will house an ESP8266, the chip I selected provides both 5v and 3....
0
votes
1answer
31 views

Low current RPi GPIO inverter

What is the lowest current way of inverting the output from a GPIO pin? I have a solar board that has an add-on that can turn a USB port power off if a LiPO gets below 3.3v. The problem is, they ...
1
vote
0answers
64 views

Need a Negative to Positive Level Shifter

I did a simple differantial amplifer for 0-3.3V output. But, as you see I got -3.3V output because gain. I need a shifter circuitry for non-negative output. Can someone help me? Thanks a lot.
0
votes
1answer
43 views

Increase voltage drop required to saturate PNP BJT to avoid noise

I have this circuit which must signal +3.3V or 0V depending on the switch status. The the switch is about 20 meters away and is getting EMI from mains. I realized that it only takes -0.7V of ...
2
votes
1answer
640 views

RS-485 using USART or UART port on STM32

On STM32F405 MCUs there are USART ports as well as UART ports available. If I need to implement RS-485 communication then which one of these should be used, USART or UART? Or are both of them equally ...
0
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0answers
28 views

How to control single 12V LED with 3,3v GPIO? [duplicate]

Heyo! I need to control single 12V LED using Raspberry's GPIO To be more exact, I need to connect 12V LED & push button to 3.3v GPIO in order to control LED (on/off) and read button push events. ...
0
votes
2answers
53 views

How to operate 1602 LCD on 3.3V [closed]

I wonder if its possible to run a common 16x2 LCD with 3.3v power supply. Its datasheet shows supply voltage = 5V. Are there any 3.3V variants of 16x2 LCD modules?
0
votes
1answer
135 views

5V Current Transducer to 3.3V Analog GPIO Input

I am trying to find 3.3V variant of the 5V Current Transducer LTS_25-NP but so far no success. Is it possible to interface this 5V analog output to 3.3V STM32F407 analog input GPIOs? Edit: I want to ...
0
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1answer
47 views

SOPs for converting a digital circuit from 5V to 3.3V

I am in the middle of an exercise in which I have to upgrade an old motor driver circuit. The old circuit has an MCU and all its logic based on Vdd=5V. I have to use a new MCU whose Vdd=3.3V. So now I ...
0
votes
1answer
85 views

HC vs LVC for 3.3V Logic

I am designing a circuit in which Vdd=3.3V. I have checked datasheets of hex inverters 74HC04 and 74LVC04 and both of these can work good at 3.3V logic circuits. If I have to select one of them then ...
1
vote
3answers
133 views

Interfacing GPIO 3.3V to 74HC04 5V

Will it be safe if I connect STM32F407 GPIO outputs (Vdd=3.3V) to 74HC04 hex Inverter inputs (Vdd=5V)? What is the best recommended method to add an inverter at the output of STM32F407 MCU? edit: ...
0
votes
3answers
132 views

Use 5v Linear Regulator and LDO 3.3V

I am designing a PCB with a STM32 microcontroller, a GPS, DataLogger and X-Bee module. The power supply is a 12V Battery. So in my project I need 5V and 3.3V, at the same time. I don't know if it is ...
0
votes
3answers
41 views

Limiting the current into Raspberry Pi GPIO pin

I have a dc dc regulator which can output .35A Current at 3.3V. I just need to check that the voltage it is producing is 3.3V by connecting it's output into one of the GPIO pins of Pi. So i was ...
0
votes
2answers
68 views

AMS vs LD vs ZLDO vs NCP in 1117 Linear Regulators

I was in the process of choosing a 3.3V Linear Regulator for my ESP based Project when I stumbled upon the different types of these voltage regulators. The 1117 regulator had different prefixes, AMS, ...
1
vote
2answers
97 views

3.3V I2C SDA/SCL but 1.8V VDD?

I'm trying to avoid the use of a level shifter in a design, but it would unfortunately require that I communicate at different voltage levels than what I power the device at. If I communicate with a ...
0
votes
1answer
35 views

Combating voltage drop on low voltage distance sensor

I have a distance measuring sensor unit that I am having some issues with, its a Sharp GP2Y0D815Z0F Digital Distance Sensor (Datasheet) that takes a 2.7-6.2v DC input. When plugged directly into my 3....
1
vote
1answer
61 views

ATmega328P running on 3.3V using a CH340G as serial to USB interface

I'm trying to use a CH340G chip with an ATmega328P that is running on 3.3V to have a simple serial to USB interface. The available datasheets for this chip seem to be very minimal so I've tried ...
0
votes
1answer
48 views

si7021 with 5V MCU [duplicate]

i need to connect Si7021 wich is an 3.3v I2C humidity sensor with Arduino, this sensor has open drain SCL and SDA drivers. is it possible to connect this sensor directly to Arduino 5V?.
0
votes
1answer
87 views

Feeding AMS1117-5V with 3.3V [closed]

I need that an Arduino NANO clone work with 3.3V. Can an AMS1117-5V give 3.3V if supplied with only 3.3V? edit: current consumption is 400mA max. the AMS1117 output current is 800mA.
1
vote
1answer
48 views

Help with supplying 3.3v to ESP and temperature/humidity sensor

I'm new to electronics. I've built this: It's an ESP-01 Wifi chip and a DHT22 temperature/humidity sensor. Now I'd like to power it with batteries instead of an Arduino. The ESP-01 requires 215 mA, ...
0
votes
1answer
175 views

5V to 3.3V for bluetooth module - Is a voltage divider ok?

So I purchased the JDY-10 BLE 4.0 module and a very small MCU which only is capable of feeding 5v. Since I'm not an electrical engineer, I've been reading a bit on the internet, and so far, I ...
2
votes
2answers
136 views

Suitable transistors for adaptive motorcycle light project

simulate this circuit – Schematic created using CircuitLab I am working on something very similar to this, Adaptive LED Headlights – Model 8790 Adaptive 2 as a hobby project. I have controller ...
2
votes
1answer
180 views

Switching a 3v motor with a MOSFET using a 3.3v signal

****I have knowledge of programming but VERY little experience with electronics.**** I'm attempting to switch a MOSFET using a 3.3v signal from an Adafruit MCU module (Adafruit Module here). The ...
1
vote
1answer
155 views

ESP8266 module emits random/garbage characters on external supply (but works on arduino's 5v & 3.3v)

Summary: With arduino's 5v & 3.3v supply , ESP8266 module emits boot messages and responds to AT commands on serial terminal@115200 baud as - boot message: ...
0
votes
2answers
167 views

Arduino Nano disconnecting from PC on plugging in 3.3v NRF24L01 into PCB

I've built this PCB which includes two I2C port expanders, an Arduino nano, inputs for buttons and encoders, and headers to plug in an NRF24L01 board. Currently, I just have code running to read two ...
1
vote
1answer
99 views

High pitch sound coming from Low-Dropout Linear Regulator (1117 3.3V) setup

I am using the below schematic to drop voltage from 5V to 3.3V (1117 3.3V - http://www.farnell.com/datasheets/2100276.pdf?_ga=2.141255921.210515873.1532314816-790306462.1508240417) for a Wifi Micro-...
0
votes
2answers
209 views

Reduce supply from 4V to 3.3V

What is the simplest and cheaper way to have 3.3V 0.5A from 4V? I'm developing a board which uses a SIM800 so it must have 4V 2A power input from 24V external power supply (I'm using a LM2596S adj, ...
0
votes
3answers
160 views

OpAmp VS Voltage Divider VS Buck Converter (Current Sensor Output)

I'm working on part of a project and I need to build the circuit that reads the current through a phase of a motor using this IC from Allegro. Assuming there will be no more than 5A, and using a VCC=...
1
vote
1answer
389 views

Alternate to LM386 for 3.3V system

I'm trying control the volume of a small speaker (8Ω, 1/4W) in a 3.3V system using a potentiometer wheel (10kΩ). I've done this in the past using an LM386 in 5V systems, but the project I'...
1
vote
0answers
147 views

Turn ON/OFF 5V 2-5A by Raspberry Pi GPIO

I need to control few 5V 2-5A devices by rpi GPIOs, which has the 3.3V logic level. I come up with a simple circuit, but I'll appreciate any ideas, corrections, suggestions. The LOAD is something like ...
0
votes
1answer
165 views

Drive 12V 1A with 3.3V 10mA (the cheap & easy way)

I found many disussions on the internet regarding this issue, but as an engineering noob I cannot get a proper circuit working :( What I want to achieve: I want to control the ignition line of a car ...
-1
votes
1answer
386 views

128x64 OLED not working on 3.3v

As the title suggests, I bought a 128x64 OLED display that would not work when powered by 3.3v. The description said that the OLED can be powered by a 3v-5v source, but I have only been able to get it ...
1
vote
1answer
119 views

How does this circuit works ? Usart level shift

I'd like to ask how does this circuit works: I understand how it works in principle, but not technically. It's a USART voltage level shifter. It's supposed to divide 5V to 3.3V by a resistor divider, ...
2
votes
3answers
6k views

Resistor requirement for 3.3v

I have a quick questions: can I safely power a LED with 3.3v without a resistor? I have some LEDs that I typically power with 5v and a 220Ω resistor, but I can only supply 3.3v at the moment. ...
0
votes
2answers
103 views

atmega8a-pu PORTC not working in 3v3

I have atmega8a-pu and not problem with 5v. but when i connect 3v3 to ...
0
votes
1answer
188 views

Connect 240v PIR motion detector to Raspberry Pi

I want to connect a 240V PIR motion detector directly to my Raspberry Pi 3. Inside its plastic case I found 2 PCBs. One is the power supply board which has a 24VDC relay, a S9013 NPN transistor, ...
3
votes
5answers
810 views

Switching input voltage, with two 3,3V inputs

I'm designing a circuit that can get its power from either a battery or a usb. The regulating of the battery and usb voltages is already done, and is regulated down to 3,3V. If both supplies is ...
1
vote
1answer
343 views

3.3V Buck-boost converter outputting voltage too high

I'm using a buck-boost converter RT6150B with fixed 3V3 output. I followed their application notes, and here's my circuit setup: Note: I used 22uF for C4 intead of the recommended 20uF for output ...
0
votes
1answer
186 views

Load sharing between 3.3V regulator and LiFePo4 battery

I am trying to design a supply for a relatively low power (<100mA) device with a LifePo4 (14500 format) battery and a USB input. Everything is running at 3.3V, and therefore I would like to avoid ...
0
votes
1answer
351 views

Wide voltage range input regulation (24V - 3.3V)

TL; DR: I need a circuit capable of handling input voltages from 24V to 3.3V (with a 10mA/5mA maximum current) and delivering 3.3V to the microcontroller (ESP32) input. Recently, I've been working ...
4
votes
3answers
470 views

3.3v regulator problem when sharing power source with LED strip

I have this circuit implemented on a prototype board. The 12v power source is a 4A switching power supply. This powers the 12v LED strip, the 7805 regulator for the Arduino, and the IRU1015-33 3.3v ...
-1
votes
2answers
292 views

LM338T Output to 5V issue with LM1085-IT 3.3V

I am using 12V , 2A DC power supply as an input to LM338T and LM1085-IT 3.3 , for 5V and 3.3V output respectively. The issue i am facing here is when these both voltage regulators are connected in ...
0
votes
1answer
90 views

3.3v current issues [closed]

I am very new to the world of electronics and have run in to an issue with a relay. I have a Wemos chip that has GPIO pins. I measured 3v coming from a pin but it doesn't seem to trigger the 3v relay. ...
0
votes
1answer
335 views

Arduino 3.3 V to 5 V to controll Stepper Driver MA860H

I'm currently working on a project with an Arduino Due and Stepper Driver MA860H. The issue I'm running into is translating a step Direction and Pulse from the Arduino Due to the MA860H. The Due has 3....
0
votes
2answers
355 views

Why is my 220v - AC/DC 3.3v transformer cutting power when relay comes on?

Being super original I've made a DIY Thermostat with an ESP8266. Being a bit of a novice (I'm learning). I've run in to some sticky bits with my kit. For the most part it works fine, but when turning ...
0
votes
2answers
3k views

Powering 3.3v-5V LED strip with 18650 batteries

I have a fun project I want to do. It's really simple: I want to power a long LED strip using a bunch of 18650 batteries. The batteries I use are 4.2v fully charged and about 3.5v when discharged (I ...
4
votes
1answer
92 views

Resistors in battery-powered LED device and Arduino

I have tiny christmas tree that has about 20 small LEDs, which are powered by 2 AA-batteries. So I'm assuming the LEDs are 3V (because of 2 AAs). This tree was bought in a store, as is. What I want ...