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Questions tagged [5v]

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

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1answer
33 views

I have a certain 9v device and I want to connect it to the same power input as my ESP32 [on hold]

I have the parts listed below. Sending a distress signal should be easy because there is a relay. However I can't figure out a good way to power them both due to the voltage difference. I tried 2x 9v ...
0
votes
1answer
53 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
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1answer
35 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
51 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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vote
1answer
81 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
32 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 ...
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votes
3answers
76 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
501 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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votes
1answer
31 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
87 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
72 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
78 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
56 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
74 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
109 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
votes
2answers
149 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
62 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
votes
2answers
885 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
votes
1answer
141 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
votes
3answers
114 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 ...
1
vote
3answers
222 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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0answers
60 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
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3answers
120 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 = ...
0
votes
1answer
102 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 ...
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vote
1answer
139 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 ...
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3answers
117 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=...
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0answers
74 views

Delay +5V to LED strip from 30A power supply

I have an LED project I'm working on using addressable LEDs (WS2812B). I'm powering these 900 LEDs with three 5V, 30A power supplies (one PS/LED strip). The issue I'm finding is that when I switch on ...
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vote
1answer
55 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
405 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 ...
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0answers
63 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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1answer
92 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, ...
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1answer
189 views

Can I use a twisted pair for 5V and ground?

I'm going to use a RS485 modbus connection which requires a twisted pair. Now I also need power, that will be a 5V line and a ground. The distance will be about 3 meters max. Can i use a twisted pair ...
0
votes
1answer
137 views

Splitting a +5V rail into 2 isolated +5V lines

I have a 5v 10A power supply that I am using to power my project. The project consists of a raspberry pi and 3 servos that are controlled by the pi through a PWM driver. The 3 servos and the Pi are ...
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0answers
56 views

Designing a Lipo Charger for 1 or 2A charge, 5A discharge

I'm looking for/designing a Lipo charger which can handle a discharging current of 5A at 5V. Obviously, the lipo's charge is 3.7V (max 4.2V, min 3.2V), so most charging circuits inside a power bank, ...
0
votes
1answer
1k views

Vcc and gnd in microcontroller on proteus

The microcontroller power pins (Vcc,gnd) in the proteus are set to 5 volts by default. I have basic regulator circuit (my vcc 3.3 volt). How can I use my circuit for microcontroller power supply?
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3answers
96 views

Dividing Current to 10 outputs from 5V source

I need to create a simple power supply circuit to feed 10 external boards, similar to a USB power hub. My power source is an AC to DC adapter measured to output 5V 10A. I need to limit the maximum ...
0
votes
1answer
67 views

Load cell amplifier inverse voltage output

I'm making a load cell modification to my Logitech G29 brake pedal. The potentiometer on the existing pedal have inverse voltage so 5V is no brake applied and 0V is max brake applied. This is inverse ...
0
votes
1answer
119 views

Voltage oscillates continously in USB Li-ion charger. Anomaly or CC/CV behavior?

I have purchased two USB boards for charging Li-ion batteries and it should have a CC/CV charging regime. So I connected the board to a 5V USB source (computer first then solar panel) and the voltage ...
0
votes
2answers
226 views

Can i switch npn transistor using 12v

I want to switch on 5V when switch is connected to 12V. I have been using relay to do this, but I am wondering if I can use NPN transistor or something similar that is cheaper and smaller than a relay....
2
votes
0answers
156 views

Help Identifying this circuit and understanding how it works

So I'm hoping to make a few modifications to my Computer case and have found that a number of the LED elements have an associated circuit to them. I want to be able to understand what I'm doing and ...
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votes
2answers
246 views

Replacing the relay in my circuit

I have this delay circuit. I am trying to delay the power to R1(which will be an android phone) by 1 second. SW10 is my SPST relay. Can i replace the relay with something cheaper and physically ...
0
votes
1answer
38 views

rc circuit for delay to charge android phone

I have made this circuit such that once switched on it takes about 7 seconds to get to 5Vs. I want to connect my phone to it (replace voltmeter in circuit with phone). Without the phone being ...
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votes
0answers
121 views

Need smallest way to achieve 5v portable battery

I have attached two images - One showing the rechargeable USB board I would like to use - The other showing two 3V batteries that have the rechargeable USB already attached and my question is can I ...
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0answers
43 views

Can you identify what type of dc jack component is this?

The little pins that connect to the motherboard broke and i need to find a replacement but i can't find a replacement.
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3answers
3k views

Powering 12V device from 5/9/12V powerbank [closed]

I recently bought the Litionite Falcon powerbank that has one of its outs designed for 5/9/12V. The 12V is at 1.5A which I thought would be enough for my 12V/0.8A camera. However, connecting the ...
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2answers
552 views

74LS189 chip overheat

I have started work on a new project of mine of building a simple 8-bit computer. Everything I have put together (clock, registers) has worked so far, until I needed to build RAM. For reference I have ...
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2answers
218 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 ...
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2answers
260 views

5V UPS circuit with NiMH joule thief backup

I'm trying to design a UPS circuit for microcontroller backup. Require 3.7-5V, and less than 50mA for 10 seconds every 15 min. Power cuts in my area are never longer than 3hours, and occur rarely. I'...
0
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1answer
344 views

Is an exhausted PSU safe to use for an FPGA? [closed]

For a project I will have 4 stepper motors,a laser module and few modules attached to the FPGA. I need around 10 amps. Clearly the FPGA can't provide enough power for all the modules. I think to use ...