Raspberry Pi Stack Exchange
Raspberry Pi Stack Exchange

Questions tagged [current]

20 questions
36
votes
3 answers

Why is a resistor needed for LEDs?

While looking for a basic task to get familiar with the Raspberry Pi and its GPIO pins, I decided that driving an LED sounded simple enough. While investigating how to go about this task I've noticed that most instructions indicate to place a…
Jason Whitehorn
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3
votes
2 answers

How to detect an electric current in a secondary circuit (12v)?

I want to detect if there is an electric current in the wire where I wrote "here > > > > > >" (on the image) The secondary circuit is a 12v circuit. How can I do this ? Thanks !
PacCol
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2
votes
1 answer

raspberry pi prevent overload current from turning on a high current motor

I am trying to use only 1 power supply instead of 2 to power Raspberry Pi and motor, but when I turn on the high current (>10A) motor, it will lead to the Raspberry Pi restarting. I guess it is something about the current overload protection? Below…
Pak Ho Cheung
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2
votes
1 answer

Powering Raspberry Pi 4 'on the move' using power bank

There are good official resources that state that recommended power supply must be 3 amps (e.g. official RPi power supply via mains). However, for use 'on the move' or remote locations this may not be practical. 5v 3 amp USB power banks exist, but…
ChiralCode
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2
votes
1 answer

Check status of float switch in water reservoir

I have a standard float switch in a remote water reservoir connected to a normal electric cable (100m+ long). I want to check with a raspberry pi if the float switch is on (i.e. water level is low) or off (i.e. water level is okay) and based on that…
crazjo
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1
vote
0 answers

What happens if I exceed the current limit at the GPIO pins of the Pico?

They say that the output current of the Pico GPIO is configurable (2, 4, 8, 12mA). What does it means ? If I choose 8mA, what will happen if I connect a bigger load ? Will the curent be limited to 8mA, or the chip will break ? If it is not limited,…
Marus Gradinaru
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0
votes
2 answers

Where to find LED values of the Raspberry Pi Pico MicroPython Learning Kit?

I am getting started with a pico and I got the Raspberry Pi Pico MicroPython Learning Kit from waveshare (https://thepihut.com/products/raspberry-pi-pico-micropython-learning-kit-pico-included) It includes 3 LEDs but it just says 5mm LED, there is…
Another_coder
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0
votes
2 answers

Max current on GPIO

I have 20 ldr photoresistors that I will connect to GPIO. They are connected pretty much like this (but without led): I have also a Hifiberry Dac2Pro connected as a hat. https://www.hifiberry.com/shop/boards/hifiberry-dac2-pro/ I have meassured…
acroscene
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0
votes
0 answers

Current draw Raspberry Pi 4 measurement results. Does anyone have more data?

I thought this would help with designing HAT power. Does anyone have similar measurements while running software and connected devices? Scant information on the current draw. I measured through the 30s start up and then pulsed a 100 mA 3.3V load on…
JSP
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0
votes
1 answer

can I use a 12v car battery to connect to a L298N h-bridge to control two 12v dc motor

I am new to the raspberry pi world and electronic in general. so I am wondering if it is safe to hook up 20 AWG wires to a car battery and have those wires going into a L298N h-bridge to power 2 AUTOTOOLHOME 6-12V Mini DC Motor also using 20 AWG.…
Rick
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0
votes
2 answers

Which is better to measure voltage and current,INA219 or current/voltage sensors?

I wanted to know if the measurement could be better, more accurate using INA219 or voltage/current sensors connected with ADCs? Also considering the time to implement both systems, which would give me more advantages?
Harli Lacej
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0
votes
1 answer

Bespoke Power Supply cable issue

I am trying to create an in-car (headrest) entertainment system using the Pi 3B with 7" screen using OSMC, when OSMC is shutdown it does not fully power off the screen, I can detect the shutdown using one of the GPIO pins, so far so good, the…
Simon Payne
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0
votes
0 answers

Measuring GPIO current with INA219

I'd like to build a simple circuit that does the following: controls a RGB LED (RPi 4 has 4 PWM outputs, so I could use 3 of them to control the LED) measures the current draw of each PWM output, with an ability to read these measurements using a…
mnj
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0
votes
2 answers

Pi 5V Pin Max Current Before Melting Happens?

I have a hypothetical project in mind I would like to pursue but wanted to ask this before sinking too much time into it. That being having multiple SPI slaves connected to a Pi Zero. From what I've read here(Raspberry Pi Power Limitations) the Pi…
AustinFoss
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0
votes
1 answer

setting raspberry pi zero to automatically power on after power failure

I'm planning to buy a Raspberry Pi Zero W to remotelly wake on my desktop pc. To do this task I need that the raspberry always stays awake; is there a way to set the raspberry automatically wake on after a power failure (such as a black out)?
user1172131
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