Electrical Engineering

Questions tagged [5v]

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Questions regarding 5V level signals, level-shifting, and circuits.

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Usb charger not charging only with vcc and gnd [duplicate]

I want to charge my tablet on the wall. And I have a charger behind the tablet and connected 2 wires to vcc and gnd, the same pins as usb female, it turns out that I can't have more than 10 mA. If I ...
3
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2answers
47 views

Minimum Current(not for switching) On a Relay?

I'm trying to understand how the pictured device works. It's a Sonoff WiFi controlled electrical relay. I was told that it is designed to control mains voltage only, and cannot be used to control a 5v ...
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1answer
99 views

Can a 5V 1Ch Relay be switched with 4V? [closed]

I have Arduino Mini Pro 5v and need to know if the Vcc will drive a 5v Relay. My Voltage output measure on the Vcc is 4.2v. Will the 5v Relay be triggered?
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3answers
127 views

Why “Supports 5V VCC operation” appeared in LVC family datasheets?

Looking into the LVC logic chip family I was aure that it is 3.3 V supply devices. One of our fellows also confirms it here. This manual dated 1999 states that LVC is 5 V tolerant (version A), but not ...
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1answer
66 views

Small project with a motor [closed]

So this project is very main function is controlling the motor spin direction and the speed witch is 0 to 5v, the all project works at 5v and i need a efficient way to controll the speed of the motor ...
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2answers
56 views

I'd like to run a 5v fan on 2 3.7v batteries

I have zero experience so if this is a stupid question please at least be kind. It seems obvious that I couldn't run the fan on one 3.7v battery but then I'm not an electronics guy. So I was thinking ...
0
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2answers
44 views

Solar RC Airplane – Trouble with Mini Solar Lipo Charger

I'm in the process of building a solar powered remote controlled airplane. My general idea was that I have 5V from the solar panels powering the receiver, the ESC, two servos and a brushless motor. If ...
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0answers
32 views

UPS power supply for both router (12V, 2A) and up board squared (5V, 6A)

I was searching for an UPS (uninterruptible power supply) to power my Up Squared Board (5V, 6A) and my router (12V, 2A). So far I didn't find something suitable but here is my idea: Take a suitable ...
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1answer
122 views

Help me identify power issues with this PCB

I bought the following UPS module for my Raspberry Pi: Power Pack Pro The module kinda works, when I unplug the power cable, the module instantly switches to battery powered mode without restarting ...
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1answer
50 views

SMPS 5V without load, fluctuation on load TOP258PN [closed]

I am using PI Expert Online (this) to design a smps circuit for 5V, 2.5A output. I already have TOP258PN IC with me so built circuit for that. Change from schematics: I am not using choke and using ...
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2answers
124 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. ...
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2answers
1k views

Can't get 5V 3A DC constant

Here's the circuit I am trying to build. I want to get 5V 3A DC output but it's giving above 7V and 4A. I have checked it in the multimeter attached in the diagram. Can any one explain what's ...
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76 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....
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1answer
75 views

Seeking simple circuit for converting 5vdc to ~15vac

I picked up some sample smart materials because I have a small project that I want to put 'magic glass' on the outside of so to speak. I picked up a couple of different sample pieces from a couple ...
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1answer
101 views

3.7V to 5V step up not providing enough current

I'm trying to power up a circuit that consists of an Arduino Nano, 3x 3W stereo audio amplifiers (PAM8403), an audio player module and 20x RGB LEDs. The power source is a lithium battery 3.7V 500mAh. ...
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2answers
99 views

How to efficiently trigger QC and convert it to constant 5V and a peak of 5A?

Introduction For a university project I started working on RGB LED Shutter glasses, which are based on the idea of a kickstarter by Macetech. However, these glasses miss some features I was looking ...
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1answer
52 views

PIR Sensor for bulb in room

This has been very long since I left electronics but recently I restarted taking interest in it as hobby. I bought some PIR sensors from Aliexpress and found it is very simple to implement if I have ...
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3answers
80 views

DC 3-12V Water pump connected to power source doesn't work

I'm trying to make a simple connection of 3-12V Water Pump to a power supply(https://www.amazon.co.uk/dp/B07D3XS91J?ref_=pe_1365641_54848841). I'm using power supply which is 5V (https://www.amazon....
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1answer
48 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 ...
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3answers
175 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: ...
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2answers
119 views

The Blue LED of ESP8266 glows continuously when connected to 5V relay output

I am a newbie. Need help on my project. I am building a project which controls a 5V relay from ESP8266 ESP-01. Since the GPIO2 gives the output of 3.3V, I am using an N channel MOSFET 2N7000 to ...
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2answers
58 views

Isolated DC/DC converter application circuit / usage

I'm trying to find a basic application circuit schematic for an isolated DC/DC converter – this one specifically: DCWN03E-12 – but I'm having no luck so far. The thing that led me to this particular ...
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1answer
64 views

Measuring USB power adapter quality using multimeter

I have heard horror stories about poor quality USB power adapter. I have a collection of no less than 20 USB power adapters, most are from cell phone manufacturers and some from small projects. I ...
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1answer
50 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?.
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1answer
104 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.
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1answer
85 views

Are there 5V battery packs available without a boost converter? [closed]

Looking for a 5V portable power source without switching or conversion noise.
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0answers
35 views

Switch resistor with n-channel MOSFET not working

So I try to amplify a photodiode signal with an operational amplifier. As I want to amplify two signals (1 for a high-intensity light and 1 for a low-intensity light) I sort of need to design a ...
0
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3answers
160 views

Correct use of op-amp to amplify photodiode in reverse bias

So I have a photodiode in reverse bias, from which I intend to measure my pulse. Currently, my schematic looks as follows: simulate this circuit – Schematic created using CircuitLab Weirdly,...
2
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4answers
593 views

Photodiode almost no mV at analog port

So I have bought a photodiode, which I intend to hook up to the analog port of my Arduino, so that I can measure differences in the light that the photodiode picks up. I realized, that when I don't ...
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1answer
56 views

where do i find max short circuit current of photodiode?

I'm trying to convert the current signal from a photodiode to voltage through a transimpedence amplifier. The photodiode is put in photovoltaic mode in order to get the greatest accuracy and lowest ...
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1answer
200 views

Why is this photodiode operated in reverse bias

Referring to the following document by NXP on figure 9. The cathode of a given photodiode is connected to the transimpedance amplifier in forward bias. To me, this seems wrong, as almost every ...
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1answer
87 views

Choosing the right capacitors and resistors for transimpedance circuit

I'm designing a circuit for a pulse watch. Therefore I naturally have an operational amplifier and a photodiode in my circuit. The job that I want the transimpedance amplifier to carry out is to ...
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1answer
102 views

Correct use of transimpedance amp

So I realized that it might become a necessity for me to use a transimpedance amplifier for a pulse watch that I intend to make. Some background: The pulse watch shoots light at 940 and 660nm at ...
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1answer
60 views

Does this photodiode need an operational amplifier?

I'm trying to make a circuit for a pulse watch, which should be capable of measuring blood SpO2. I use 2 LEDs for each wavelength (respectively 660nm and 940nm) to shine at the upper wrist. The ...
0
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1answer
216 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 ...
3
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1answer
149 views

Powering 9216 leds @5V, @24V with converters

I am struggling with a power supply question. I would like to power up and control 9216 LEDs -- strips of 144 LEDs/meter (WWA SK6812 - just like the RGB kind). These are powered at 5V and draw 43.2 ...
1
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1answer
43 views

Driving power + USB over cartridge connector [closed]

I hack old hardware (mostly microcomputers) by putting new insides in them, but I still consider myself a newbie when it comes to electrical engineering, so please bear with me, because this question ...
0
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2answers
262 views

2.8V to 5V conversion not working as it should. Why?

I'm using an arduino Leonardo clone (SS Micro) who works on 5V logic only, but has also a 3.3V output for powering devices. I'm interfacing it with a breakout board TOF sensor, the VL6180. This ...
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2answers
197 views

Tachometer Signal Voltage Reduction

I am working on a formula style car and creating a digital dash based on an Arduino. I currently have a signal from the ECU running at 12v DC and a varied frequency depending on the RPM of the engine. ...
3
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2answers
928 views

Having trouble in GPIO output, 220 V to 5 V signal

I'm not an electric guy, I'm just trying to build a small circuit to sense 220 V with my Microcontroller (RPi). But I'm getting either 5 V or 1.3 V on a GPIO wire. I can't understand the problem. I ...
0
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2answers
326 views

Two 5V Raspberry Pi UPS Idea

I need a cheap, reliable and easy to build UPS for my raspberry pi server. The UPS must maintain power for a maximum of 1 hour. Based on what I found on the internet,I came with two solution. (see ...
0
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3answers
118 views

I'm planning to put lots of phone chargers on one circuit, how to calculate this

This would be primarily for samsung S7 devices. Would like to be able to charge, say, 256 of them. They will work in groups of 16, trying to design the power flow of this. Was imagining that each ...
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3answers
392 views

True 5V CPLD other than PIC/Altera ATF150*?

Are there any True 5V CPLD's families still in manufacturing other than PIC/Atmel ATF150*? I am talking not just "5V tolerant IO", but rather ones with 5V VCCIO, able to drive 5V loads without ...
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3answers
126 views

Can a 12V power supply provide more than the rated current at lower voltages?

This might be a silly question but if I'm using a 12V power supply rated to provide 5A does that mean that if I was to regulate the voltage down to 5V I could theoretically draw 12A at 5V? If Watt = ...
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2answers
259 views

How to reduce noise in this circuit?

I'm using a Raspberry Pi in a circuit I'm building that includes a few elements. Elements in the circuit: PWM driver to control 3 servos Mic board for recording Class D Amplifier that drives 2x3W ...
1
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1answer
140 views

micro blown up with 3V?

I'm attempting to make a 12v blinking light that turns off with a high signal and since I've got some 5v arduino pro minis I though I might do it with them. So I put together a program and a plan My ...
0
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3answers
183 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
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1answer
73 views

REF02 not working - 4 channel 5v DAC circuit, star gnd connection, stripboard layout

I've connected my circuit as in the diagram, with a 15V PSU powering it (both amps are connected the same way) - but the DAC seems to be drawing too much current for the REF02 to handle, even though p....
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4answers
1k views

5s backup by 1F 5.5V Super Capacitor

Can I have about 4 to 5 seconds backup by 1F 5.5V Super Capacitor? Power supply output voltage: 5v 600mA I need 5v 0.5A for my system. I want to use it as ups for only 4 to 5 seconds so I wasn't ...
0
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0answers
67 views

Varying performance of mbed, depending on Power Supply

I've written a very basic program (without the mbed library) to turn on all LEDs on an mbed board (https://os.mbed.com/platforms/mbed-LPC1768/): ...

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