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Questions tagged [3.3v]

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

2
votes
2answers
126 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
77 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 ...
0
votes
0answers
54 views

Power GPRS modules from 3.3 V or 18650?

I need to know whats the proper way to power a 4V module (capable of draining 2A pike, or 250mA for continuous) from a lithium battery, or 3.3V regulator. Particularly I am working with ESP32, ...
1
vote
1answer
73 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
0answers
94 views

SOT-23 marked “N27 pF”. What IC is this?

I can't recognize this IC (see attached picture). It's an SMT SOP23 with 3 pin only, and it is marked "N27 pF". The first pin on the left is connected to a 5V line, the single pin on the top is ...
0
votes
2answers
85 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 ...
0
votes
0answers
53 views

Bi directional logic level converter not dropping voltage to ground

I made a Bi directional logic level converter according to the following document https://cdn-shop.adafruit.com/datasheets/an97055.pdf but am experiencing a weird behaviour. One side is connected to ...
1
vote
1answer
85 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
135 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
96 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
177 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
75 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
109 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
115 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
84 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, ...
1
vote
3answers
1k 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
78 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
99 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
688 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
220 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
0answers
27 views

Using a boost for Servo powering and Issue with MOSFET selection

I am working on a project to perform a high torque operation using a servo. The supply is from a power bank(generic 5V). The torque is not enough to perform the operation unfortunately. So I thought ...
0
votes
1answer
136 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
212 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
401 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 ...
0
votes
0answers
289 views

Trouble powering ESP8266 ESP-01 module

I'm having trouble powering an ESP8266-01 module from a 3.3v low dropout regulator. Tried an LM317 (configured for 3.3v), and lately I've been testing a IRU1015-33. This regulators usually work fine ...
-1
votes
2answers
186 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
83 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
245 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
242 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
2k 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
88 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 ...
2
votes
2answers
329 views

How can I return an Arduino digital pin to floating state?

I am trying to setup a programmed reset function for a 3.3V BlueTooth module that resets when its reset pin is pulsed LOW for a short period of time. There is a 47K pull-up resistor in the BT module ...
0
votes
1answer
2k views

N-channel MOSFET used to control 5V relay from 3.3V ESP8266 pin

Today I "played" with a relay for the first time. I only had an N-channel MOSFET available (an IRLZ44N) and wanted to control the relay from an ESP8266's GPIO pin - i.e. use a 3.3V signal to control ...
3
votes
2answers
284 views

mic5504 + esp8266 = going mad

I've a board with an esp8266ex and a flash IC. The main power rail is +5 and it goes into a MIC5504 for 3.3 voltage regulation. The enable pin of the MIC5504 is tied up with a 10k resistor to the +5 ...
0
votes
0answers
468 views

VGS(off) for JFET in AGC circuit

I want to use a well known AGC circuit (see below) with 3.3V instead of 5V. The description of the circuit can be found here, and state the following about the JFET: Other JFETs with VGS(OFF) of 5V ...
1
vote
1answer
313 views

LDO 3.3V Overheats on DC input and no load

XC6206P332MR 662K 3.3V 200mA TOREX LDO Voltage Regulator SMD SOT-23 The capacitors on Vin and Vout are not too close, maybe 1cm away from the pins, I've tried anything from 0.1uF to 22uf, Im powering ...
1
vote
2answers
444 views

How to drive multiple LEDs from a Li-ion battery (with varying voltage)?

I want to supply constant voltage to my LED's but the supply varies from 3.7V to 4.2V (Li-ion battery). I cannot use 3.3V voltage regulator as it will need at least 4.3V voltage at the input but my ...
0
votes
3answers
1k views

Can is use the 2N7000 MOSFET to switch 12v from 3.3v?

I want to control some 12V solenoids (SH-04215-015) from a Raspberry Pi Zero W. I believe I need to use a MOSFET transistor to switch from the 3.3V of the GPIO to the 12V the solenoids need. I'm not ...
1
vote
5answers
1k views

3V LED Pulse Circuit

I am trying to make a very compact and lightweight circuit that will cause an IR LED to blink on and off at a constant rate, preferably at least once per second but the flashes can be more spaced out. ...
2
votes
1answer
316 views

How to use 74LS245 to level up signals form 3.3V to 5V?

I am using FPGA 3.3 V outputs to drive 16x4 character LCD (5 V). I went through the data sheet 74LS245 and found this can be operated at Vcc 5 V and accept input voltages from 2 V. I am confused ...
2
votes
2answers
536 views

3.3V step up to 5V using BJT

I'm using an Arduino Blend Micro with outputs that provide only 3.3V and I need to control a MOSFET that needs 5V on its gate. Can I step up the voltage from 3.3V to 5V using a single BJT?
0
votes
2answers
1k views

How to shift-up logic signal from 3V3 to 5V for NeoPixel [duplicate]

I'm working with NeoPixel led strip and a microcrontroller which run at 3.3V. As you can read in the NeoPixel documentation using a micro with 3.3V out on pin require the ...
0
votes
1answer
103 views

PMOS reverse polarized - 12v light

I've this circuit: simulate this circuit – Schematic created using CircuitLab I have a doubt, when I press the SW1 the LAMP1 turns on, when I press the SW2 the light turns on but the P channel ...
1
vote
1answer
134 views

Having trouble using Adafruit LM3671

I'm trying to make use of an Adafruit PCB with an LM3671 on it. Note on the PCB layout how the EN pin is connected to Vin via a 100Ω resistor. On the 3.3V output, I've connected a 100Ω resistor and ...
1
vote
0answers
122 views

RXD line problem

Hi below is my setup block diagram to understand Setup description: I have two board , board 1 and board 2. Board 2 is third party board we purchase. Board 1 has on board SMPS which convert 230VAC to ...
1
vote
1answer
994 views

AMS1117-3.3 from 5VDC show 0.09vdc

Hey all I am having an issue using this AMS1117-3.3 SMD: According to its documents it says its either a fixed or adjustable version? So I hook it up as I see in the documents: The left pin (1) ...
0
votes
2answers
107 views

best way to regulate 3v3 from 25.2V (DC)

The circuit maximum voltage is around 25.2V so this is the supply im using, I wonder which one is the best way to get 3v3 with less components count and keeping it cost effective, space is a problem, ...
0
votes
5answers
1k views

How to blink led (~5Hz) at 3.3V (coin battery) with minimal component to save power?

I need to build a circuit to blinka led (about 5Hz) with a coin battery, so on 3.3V. Main specifics: Single coin battery (3.3V) The led is an SMD5050 with 3V and 100mA max. I would save battery as ...
1
vote
2answers
1k views

How convert a 3.3v PWM signal to a 5v PWM signal

I want to drive an array of leds with a transistor, no more than 240mA the things is that im dimming them with PWM works fine with 5v PWM but im having problems with 3v3 uc because with full 3v the ...
0
votes
1answer
393 views

Fuzzy 3.3V from MC34063

Recently I've made simple buck regulator based on MC34063 from TI. I want to use that to power my SMT32 base application. Voltage on input varies from 9-26V. I've put some part on general purpose ...