Questions tagged [5v]

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

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-2
votes
0answers
79 views

LM7805 regulator IC heating up at no load

I have connected two LM7805 ICs with same inputs and grounds to a 7.4V battery but different outputs, also placing the capacitors of 3.3 microfarads and 1 microfarads (since I didn't find 0.33 and 1 ...
1
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1answer
29 views

How to keep a stable output voltage from changing input voltage

I'm learning about solar panels and bought a 6V panel and a 3.7V Li-Ion battery as well as a solar battery charger, all from adafruit. I also got a boost converter thinking that the output of the ...
2
votes
1answer
68 views

Steal 5v from USB Module in 3v Mode

My project includes an ESP8266 (runs at 3.3v) and a USB C-Serial breakout. The USB module can optionally run at either 5v or 3v, and there's are solderable jumper pads to make that switch. Here's ...
-1
votes
1answer
83 views

What is happening when I apply 5V DC to the DC end of a 12V AC to DC adapter? [closed]

The question is in itself a little bit confusing but I will try my best. So I have a normal 12 volt (1 amp) AC to DC wall charger, nothing fancy about it. I use that to power a fan, which works great ...
0
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0answers
27 views

NodeMCU - Are all GND connctions born equal?

I'm designing a PCB which is based on NodeMCU board in its core. On NodeMCU there are some GND pins, most of them are to serve digital outputs/inputs, or external sensors which operate on 3.3V. Vin ...
0
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0answers
48 views

VCA on 5V powersupply

I've made a VCO and ADSR-generator with two Arduinos. The VCO uses a DAC made with a resistor ladder, the ADSR-gen uses a 12bit DAC. Everything is 5V powered (USB charger of 1A). In my search for a ...
5
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2answers
166 views

Capacitor selection for LM3940 LDO regulator

My project requires 3.3v for operation. For the simplicity I want to power it with USB sources and this makes me to add step-down converter/regulator to get 3.3v from 5v line (let's omit input power ...
1
vote
1answer
75 views

Using 2 5V pins to get 10V [duplicate]

I want to to my RaspBerry Pi 4 with an old small CPU fan. However it's a 12V fan. Is it possible to use 2 of the 5V pins on the board to total to 10V? Sorry if this is a dumb question. I haven't ...
0
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2answers
133 views

How to amplify a 0-5V PWM Signal to 0-12V, 10A

I need a Power amplifier which amplifies a 0-5V Arduino-generated PWM Signal to a 0-12V Signal with 120W, for powering a ZVS induction heater. Linearity is not important because i can correct the ...
0
votes
2answers
79 views

Charging a battery without overloading the rest of the circuit

I have a charger circuit (BMS) V1 which charges my LiFePo4 V2 battery, the battery also attaches to a circuit which can take a little more than 3.3v, however if for what ever reason the battery fails ...
1
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2answers
132 views

Why these tutorials don't care about wires when using 10A with 5V to light up strip LEDS?

One popular project I want to do with my Arduino is to light up 150 LED Strip of 5 meters (WS2812B). Here is my project: So, I have a power supply of 5V 10A (ALITOVE 5V 10A AC to DC Power Supply). ...
22
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4answers
5k views

5 V home network

I'm planning on adding multiple IoT devices in my house, and I'm looking for an elegant solution to power them all. They'll all need 5 V, a small number of them (cameras) would draw up to 2 ...
1
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1answer
93 views

How to power a device using a USB port instead of AA batteries?

I have a device that uses 3 AA batteries and I would like to power it from a USB port instead. As I understand I will have to use resistors but I have no idea on which ones. I have found the ...
1
vote
2answers
109 views

Best way to connect 5V to GND from ESP (3.3V) - transistor or optocoupler?

First of all: I read through some of the suggested topics (i.e. connecting a 5V relay to an ESP), but to my (limited) understanding, this seems not to be the problem I'm trying to solve. If it is, ...
0
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3answers
91 views

How to interface a C64/Atari joystick port with the ESP8266 (level shifting from 5 to 3.3V)?

I'm working on a device based on an ESP8266 (Wemos D1 Mini) that shall be connected to a C64 or Atari 8-Bit computer's joystick port. At the same time, a normal joystick could be connected (signals ...
0
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0answers
53 views

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
votes
2answers
86 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 ...
0
votes
1answer
102 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?
2
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3answers
156 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 ...
0
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2answers
112 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
61 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 ...
1
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0answers
85 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 ...
2
votes
1answer
220 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 ...
0
votes
1answer
269 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 ...
-4
votes
2answers
283 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. ...
3
votes
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 ...
0
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0answers
81 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....
1
vote
1answer
82 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 ...
0
votes
1answer
187 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. ...
1
vote
2answers
145 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 ...
1
vote
1answer
54 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 ...
0
votes
3answers
136 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....
0
votes
1answer
55 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 ...
1
vote
3answers
375 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
2answers
157 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 ...
0
votes
2answers
105 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 ...
0
votes
1answer
68 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 ...
0
votes
1answer
57 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
128 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
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1answer
94 views

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

Looking for a 5V portable power source without switching or conversion noise.
1
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0answers
40 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
votes
3answers
288 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
votes
4answers
691 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 ...
0
votes
1answer
150 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 ...
0
votes
1answer
614 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 ...
0
votes
1answer
109 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 ...
0
votes
1answer
112 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 ...
0
votes
1answer
65 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
votes
1answer
342 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
votes
1answer
222 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 ...

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