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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59 views

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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82 views

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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41 views

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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105 views

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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70 views

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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88 views

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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54 views

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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66 views

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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38 views

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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136 views

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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34 views

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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61 views

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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67 views

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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24 views

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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102 views

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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72 views

low voltage radio frequency amplifier [closed]

Is it possible to build an RF transmitter final amplifier that can be powered by a single lemon as a battery? (maybe 0.9 Vdc at 1 mA, with suitable electrodes, when fresh) Desired operating frequency ...
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101 views

Voltage Limitations of a header being used as a voltage selector

I have an application that takes a reference voltage. These voltages could be considered 'low voltage' as they range from 0 to 1000 V. Below is a reference schematic of what I'm trying to accomplish, ...
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87 views

What to use for neutral protection

I need information on "the protection of distribution system through effective grounding techniques." I want to know the possible protection schemes for neutral as fault current or return ...
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49 views

How can I electically isolate two sprinkler controllers 24VAC working on the same output (master valve)

I have an old 24 zone sprinkler controller and I'm trying to move 16 zones to a "smart" sprinkler controller. I have a master valve that has to be switched on to provide water downstream to ...
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465 views

how to calculate hysteresis resistor value TL431

I'm creating a small ESP32 based robot controller board. Partially as a self learning experience (mech engineer, self taught on eletrical front but this is for hobby use :P) and partially because it ...
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94 views

back gate effect in low volatge circuits

1- In some circuits (Low voltage ones) the body of the pmos is connected to the gnd and nmos to the vdd. i wanted to know the reason behind this technique or in others words what's the idea behind ...
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109 views

270a DC inrush, 130a DC nominal load. 14 vdc supply. Ways to limit circuit to no more than 11.5 vdc?

What device can be installed between the glow plug relay and the power leads to the glow plugs, to allow ANY voltage under 11.5 vdc, but allow no more than 11.5 vdc, regardless of how much higher the ...
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78 views

Nodal voltage magnitude properties of electricity distribution networks

I am wondering how to know about an electric bus according to its measured voltage magnitudes (possibly and its corresponding real power injection profile). Following assumptions can be made: One ...
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240 views

Solution for how to drive a P-Channel MOSFET when Gate/Source voltage is too low?

I have used this forum to lookup solutions and suggestions from time to time but this is my first ever post! There are many great P and N-Channel MOSFET Questions and Answers in here, but I cannot ...
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68 views

Is upsized reactor allowed for the comparitively less motor HP?

We have a LV-MCC in our commercial outlet having a 480 VAC, 15 HP VFD with line and load reactors in series with it. The VFD is sized for 22.0 A (normal duty), the motor has a horsepower rating of 10 ...
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107 views

Controlling 120v line with a 12v switch on a different line

I have 10a 120v power sockets in my garage that currently doesn't have any switch on it and powers some overhead lights that I have plugged in. Separate to that, I have a 12v circuit powering various ...
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157 views

4S Lithium Ion Low Votlage Cutoff

Disclaimer: I'm not an electrical engineer, and most of what I've done so far has been from researching similar designs on the interwebs. I'm just a tinkerer with a soldering iron, so please excuse my ...
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60 views

Combine voltage sources [closed]

I have a Baldor DG6E generator. It must produce 120V/240V but I bought it and it has three wires as outlets - every one produces 120V. I want to combine two wires to produce 240V. How can I combine ...
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105 views

How to drop the voltage slightly (~100mV) for a MCU mostly in deep sleep?

How to drop the voltage by a low value (let's say <150mV) without wasting current to supply a microcontroller that spend most of its time in deep sleep mode? I'm working on a board with a ...
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3answers
78 views

Regulatory considerations for 500W, 400V DC power tether

I'm working on a robotics project where we intend to deliver ~500W of power over a 1000 ft tether. The current plan is to run ~400VDC down the tether on a pair of 16 AWG wires. These power wires will ...
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216 views

Plate current use of 12Ax7 vacuum tube at low voltage

Does anyone know the current used by at 12Ax7 (or similar) vacuum tube when in normal (triode) operation using a plate voltage no more than 10VDC? I'm not considering the heater current (~300mA at 6....
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108 views

Using a JFET as a voltage limiter

I have a circuit that runs on 1V up to 15V DC. I want to attach a low-power battery-level (1.5V) device to this supply rail, and have it work over the broadest input range possible (yes, it will cut ...
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3answers
91 views

Robust low battery cutoff

I am building a 5V DC charger for an offroad motorbike. The main goal is to use this to charge/power a mobile device/phone/tablet whilst travelling/camping. If space allows maybe also a GPS tracker ...
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2answers
128 views

How to turn on an LED when voltage drops to low?

I have an old vehicle from the 70's and it has a gauge for oil pressure. I want to add a 12v LED to the dash that will light up when the oil pressure is too low. The installed sensor on the engine is ...
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1answer
170 views

How to identify a low voltage transformer

Not 100% sure this is the correct forum for this question. If not, I apologise. I am trying to identify this transformer. It comes out of a Paradigm PDR-10 subwoofer amp. I believe it is bad as ...
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1answer
25 views

What is the typical load resistance for a thermostatic circuit?

I’m looking at retro-fitting a dehumidifier with a condensate removal pump to eliminate the need to empty the bin (daily during the summer); specifically this pump. This pump has a safety switch ...
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2answers
87 views

Detecting activity on LVDS line

For some test equipment I have an LVDS line running at 100 Mbps. I would like to make an Arduino Due (because I use this for other monitoring in the test) detect activity on the LVDS line. Using a (...
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1answer
96 views

Wiring case fans in parallel to a USB cable with an inline switch, still spins slowly

I have 2 separate projects one is a case for a Raspberry Pi 3b+ as NAS server and the other is a media cabinet. The NAS kit has 4 30mm 2-wire fans (5V 180mA) and a wired in USB cable that is plugged ...
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99 views

Storing low-voltage power?

I'm doing a project for my school which requires harvesting body heat to generate electricity. Now, I've tackled this problem by using TEG, on the chest. Now, the problem is that this TEG is estimated ...
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2answers
194 views

What is causing a white scale buildup at copper pin connection on LED light sticks and how can they be cleaned?

Can someone explain what is causing this white scale to appear on the copper pins and on the block of this LED light connection? The seal at the connection is supposed to be watertight. On occasion, ...
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1answer
195 views

Low voltage / high current rectifier using MOSFET

I was wondering if the following approach to make a very low voltage / high current rectifier (~0.1 V, 1 kA DC) from 230 V AC has any sense or not. Aiming at simplicity rather than effectiveness, I ...
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111 views

Effect of electrical arcing on the system voltage

What will be the effect of Electrical arcing (between phases or between phase and neutral) in a 415V three phase system in the downstream voltage... Will it just act as a load ( let's say the arcing ...
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2k views

How to Size Line Reactors and Understanding Reactor Specifications

I've got a 600 VAC, 75 HP VFD that I want to place line and load reactors in series with. Usually, I find charts like this that give me a horsepower table to follow as they are the easiest to use. ...
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98 views

Can I use diodes to protect power supply outputs?

(Note, this is my first question on this site, please point out if there is something that I am doing wrong here.) I have a thyratron that requires two separate power lines to attach to it. The two ...
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65 views

What is the correct instrumentation to measure a pulse height of 10's of microvolts with a pulse width of 10's of picosenconds?

I'm working with a sensing material and want to better understand its response. I have the theoritical elements worked out, but now want to begin testing and have no idea what type of tools/...
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89 views

How to make a power supply cable for a 10.5V 4.3A laptop OR how much higher voltage can I use

Let me preface this by saying I've spent countless hours researching and learning what I can about electronics before asking this, and I cannot find a clear answer to this. So sorry if this seems like ...
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72 views

Can I amplify a thermocouple Signal with the GS8332-SR OP-Amp?

Theremocouples have a very small voltage of around 0.4mV/10C. K Type Thermocouple Voltage Table I want to amplify that signal so I can read it with an ADC on my Arduino Microcontroller. The Voltage ...
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59 views

Modeling the thermal part of the Time-current curve

G’ day, I am working on designing protection devices for my research work and I am struggling to model the thermal part for the low voltage circuit breakers based on IEC standards. Based on the ...
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2answers
669 views

Why is 100 volts or less generally "low voltage" and "safe"? [closed]

In the United States in many state jurisdictions, wiring that operates either exactly at or below 100 volts is not required to be installed by a licensed electrician, and no site plan, building permit,...
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153 views

How to measure uV voltages buried in noise?

I'm working on a project in which I am analogly processing ultra low signals. The phase, harmonics and signal shape are critical to circuit functions. The signal on the input comes from an antenna ...