Questions tagged [low-voltage]
Low voltage refers to voltages in a range from 1) 50–1000 Volts AC [Vᵣₘₛ, rms…root mean square] and 2) 120–1500 Volts DC according to standard IEC 60038 of the International Electrotechnical Commission.
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I need to build a high current, low voltage buck converter
I am trying to power a 14 mΩ resistive load at 0.3 V 21.5 A to add some buffer to the design I'm trying to design for 30 A, since the load can change.
Without going too in depth the load is a new ...
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Why is a spliced USB extension cable frying USB Drives?
I cut a functional USB-A extension cable in half, reconnected the wires, and plugged a USB drive into it. This cable killed three USB Storage Drives. Why?
The above photo shows the cable. I know, I ...
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Switching low voltage with high accuracy
To do some discharge tests, I want to connect 1.5 V batteries to very low resistances for a short amount (10 - 200 ms) of time, then have them disconnected for at least a couple of seconds.
What would ...
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LED light data issue
This has been driving me insane for some time now. I can't seem to figure out why my LEDs have issues with communication. They have plenty of power supplied. I broke down my entire circuit to the most ...
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Using skin to close low-voltage circuit
I am trying to create a ping pong ball sized light-up ball that should light up when held in my hand, as in the 80's toy inspired by the movie/television series "Star man".
The circuit must ...
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Low voltage boost-converted versus high voltage on capacitor
Let's say I have a 7.4 V Li-ion battery that I boost-converted to 36 V, and I have a 36 V Li-ion battery. I want to know if a charged capacitor from a boost converter would release energy like a ...
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Are there any substitutions for depletion PMOS transistors?
I am currently building a low-voltage cut-off circuit. When the battery is under 10 V, the microcontroller should pull the battery power to ground which will blow the fuse with high current and cut ...
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Low voltage to drive LED flash (not successful in simulation, but works on breadboard)
I first did this circuit on a breadboard, except I originally used a light-sensitive resistor, which is around 1 kΩ at daytime and above 160 kΩ in darkness.
It oscillates with LED as capacitor adds up ...
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7-meter cable between gas meter and microcontroller: too long?
My gas meter has two GND / PULSE pins that trigger a short pulse (probably +3V or +5V) each time 0.010 ㎥ has been used, for use with domotic equipment. There is no power plug in this basement, and I ...
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Battery over-discharge protection
I am studying NiMH battery charging and using such a battery on a board to feed other circuits. I would like to add a protection circuit that provides protection for over-discharging the battery at ...
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Fusing power injected LEDs from both sides [closed]
I am involved on a project where we will be installing thousands of LEDs (WS2812B Addressable strips) on the floor. I have a question about about fusing and if there is a more efficient way to go ...
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Low-voltage vacuum tube amplifier design
Amateur radio HF frequency amplifiers using transistors commonly can be powered with around 12 to 14 VDC, or even lower voltages, for QRP transmitters.
Tube amplifiers seem to require DC power ...
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Thermoelectric EMF problem for low voltage measurement load cell
The resolution of a load cell is highly dependent on its capacity. That's because the higher the resolution and the higher the capacity, the smaller the voltage change. For example, many companies ...
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Low voltage connector identification?
Can anyone identify the female and male connectors in the picture? Thanks
Here are some more pics Thank you.
1.56mm from pin to pin. So it should be a JST 1.25mm 2 pin micro?
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Powering and dimming a few hundred light bulbs
I want to power a very large light fixture: it has 273 G4 socket light bulbs. The bulbs I found for the thing are 12 V 5 W ones, incandescent.
So the question is how to power the beast (as it is 1365 ...
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Transistor to switch low voltages (< 1V)
I am building a system for pulsed electrodeposition, where I would like to switch very low voltages (0.3 - 1.0V.) I am not sure about the type of transistor to use for that. A BJT would drop 0.7V, so ...
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potential free output signal with AC as input (no mechanical relay)
Here's what I'm trying to do:
I have a a bunch of 24vac actuators running of a 24vac XFR. The actuators themselves are controlled by a thermostat. What I need is a isolated 0v signal when any of them ...
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Replacing button switching 1.3V with microcontroller
First, sorry, I am a total hardware beginner (and 20 years since I had some electronics classes on the uni).
I want to replace a mechanical switch (well two switches…) with something driven by a 3.3v ...
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How can I select a suitable cable with these characteristics: 690 V, 550 A, 1 km long, AC three phase underwater cable
How can I select a suitable cable with this characteristics:
The cable is connected at one end to a 690 V power generator that is between 6 and 40 meter below the surface of a big river and converts ...
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Two battery control
I have two Li-ion batteries in my system. (7.4 V 12000 mAh and 7.4 V 2200 mAh; also they have BMS). The larger one of the batteries can be easily removed and installed from my system, so I can charge ...
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High Voltage & Low Voltage PCB Design
I am trying to make a PCB that acts as a "Raspberry PI HAT" and allows me to connect the raspberry to different sensors. Specifically, I'm having difficulties in defining the design rules ...
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Is it okay to charge a deeply discharged Li ion cell below 1V?
I accidentally discharge my lithium cell to 0.45V. Is is okay if I try to revive it by charging with 10mA of current till it reaches 2.5V?
cell capacity is 4000mAh.
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Blocking oscillator, Slayer exciter drawing too much power
I am trying to build one of these using an air-core coil. I got it oscillating but have to cut power off after 4 seconds as it starts to heat up (can't hold it with my fingers.) The transistor is not ...
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12V-only (and no 110V/220V) household electrical installation [closed]
Power outlets are in 220V/110V in houses for historical reasons (light bulbs and other appliances probably required >100V voltage) but nowadays as:
we use a USB charger 220V->5V for phones, ...
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Single vs two pole breakers - Single phase loads on IT power with distributed neutral
Are two-pole breakers required on single-phase 230 V loads when connected to a 3-phase supply with IT earthing system (with distributed neutral) in Germany?
Where in the standards is this requirement ...
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3 phase low voltage signal generator
I want to create my own 3 phase signal. However, instead of it peaking at 230V AC it must peak at 5V AC.
This generator will be used to feed a secondary unit that uses this signal to perform its own ...
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Low voltage asymmetric duty cycle oscillator
I'm designing a low voltage (1.6 V and less) LED decoration.
The source voltage is a low power, high impedance energy harvesting source.
With the following characteristics: deliver between 0.8 and 3 V ...
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Can I use a 1kV capacitor for a 5V circuit?
In a different question, it was asked if you could use a relatively higher voltage cap in a 5V circuit (35V cap). It seems that's ok, but I want to know if that logic is still applicable towards the ...
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Regenerative Drive VFD when drive is a major % of network load?
I'm in the process of designing a new facility with about 50-60 VFDs in the 5-10 HP range, another 5 VFDs in the 100-225 HP range, and then one burly beast at 1000 HP. I've been looking into various ...
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Why do we not see multiple or parallel DC PSUs?
A friend mentioned that his home router had blown its 12V PSU recently and had to be replaced.
That got me wondering - Servers and routers can have isolated dual PSUs for exactly this condition, but ...
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Design a flashing circuit that uses PWM signal and MCU signal to control when it is on and off
My team and I are working on the low voltage systems of a solar car and have an issue with figuring out how to flash the turn signals on the car. The options we are exploring include:
Using a 555 ...
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Help with constant current load hysteresis
The circuit above is a constant current load based on an LM358 comparator.
It is very useful to measure the capacity of lithium-ion batteries.
The original circuit I found online had a 5V supply but ...
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Low-Voltage Unidirectional Ground-Level Shifter
I am trying to interface the status LEDs of a third-party device to the GPIO of my ESP32. I am using internal pull-ups on the ESP32 inputs and trying to trigger on the voltage drop that occurs when ...
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What will happen if I use RCBO where there is no neutral in the system?
I need some help. Could you please go through the scenario and try to answer my query below?
This system is installed in a ship where there is no neutral connection available.
A 440V/220V step-down ...
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Isolating low-current, low-voltage digital signals
I'm working with a battery-powered sensor that allows reading its measurements using two digital signals - a clock and a data line. The clock speed is abount 3kHz. In addition to those two signals, ...
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Low voltage MOSFET gate drive
What is the best way to drive a MOSFET with low voltage?
I have encountered several projects where power from a battery is used to drive motors or source a DC/DC converter.
In most cases, we used an ...
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Can I use a multimeter to verify if RX/TX of a device is working?
To summarize a problem: My electricity meter uses a HAN interface (via M-bus) to transmit the meter's data every 10 seconds. Apparently this HAN interface can be enabled/disabled by my energy provider....
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How to wire two open-drain logic outputs to a three pin bi-color LED
I am very new to working with electronics; my main experience is in programming. I am working on a project and intend to use this MCP73833/4 Li-Ion Charger. It has two "Charge Status Output" ...
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How to block low voltages in a very low current circuit
I have a circuit circuit fed by a 48V nominal lithium battery source. I'm using a few simple resistors to divide the voltage down to a suitable range to drive a p-channel mosfet gate. When the battery ...
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How can I block low voltage?
I have added a picture about my circuit. Please look at the picture. How can I safely provide the logic in the image? What kind of circuit should be in low voltage control block?
I have to cut off Vo1 ...
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Update very old, very low voltage (10V) Nutone doorbell system to new 16V chime
I have a Ring video doorbell that is connected and functioning to the old doorbell wires, which I measured at 16V.
I also have a old Nutone Scoville 10 V, 5 VA transformer tucked in a very hard to ...
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Safety with low voltage high current safety
For my work, I’m working on a project that uses a power supply that outputs 42A DC at 5V limit.
While I know that 5V is nothing if I were to come into contact, poor grounding can still cause flashes ...
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Can I power a 35 Watt light fixture over a thermostat 5-wire?
I would like to add this light fixture to my ceiling in an area that only has a thermostat 5-wire coming out (something like this). (The other end of the thermostat wire travels about 15 feet, ending ...
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Can an Adjustable Circuit Breaker be adjusted while Energized?
For a Low Voltage Circuit Breaker, such as the Legrand DPX3 630, 3x400A, 36kA, 400V, we have adjustment dials to change the properties of the magnetic (Magnetic adjustable from 5 to 10 In) and or ...
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DC-DC boost converters in parallel to run DC motor
Our aim was to power the motors of our bot (which were selected according to the torque requirement of our bot) using a single AAA Battery but due to limited time and and the difficulties in ...
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Relay: wetting contacts before using sub-wetting current
I'm considering using small signal relay for my application since I need to switch shunt resistors to measure currents from 1uA to 10mA (two shunts) with voltages from 0V to 5V.
Now, it's clear for me ...
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Modifying the MT3608 DC-DC Boost convertor
I am using the DC-DC boost converter MT3608 for a project where my input ranges around 1 V. Is there a way to modify the circuit so that the boost converter can operate at voltages less than its ...
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How to protect low-voltage hardwired device against 120 V AC miswiring ? (I need a resettable solution)
I need to protect a hardwired device, made for AC low-voltage transformers (e.g. doorbell), from miswiring to a 120 V AC power line. It actually occurs no matter how many warnings I put everywhere.
...
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Low voltage beak away/tension release connectors for building to building overhead cables
Are there low voltage breakway or tesion release connectors that should be used for overhead, building to building applications?
The background is we are running a single pair of speaker cable, and a ...
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Low voltage directive
I just want to check my understanding of LVD.
I have a portable device that operates on a 30V DC input. Its output is less than 30V DC and is powered by a wall plug (UK 240V) that I supply.
Am I ...
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