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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51 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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40 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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34 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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2answers
48 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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76 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
69 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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2answers
61 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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1answer
44 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
79 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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79 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
72 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
22 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
49 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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35 views

Wiring Case fans in Parallel to a usb cable with an inline switch, still spins slow

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 i have 4 30mm 2-wire fans (5V 180mA) and a wired in usb cable that is ...
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53 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
163 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
72 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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28 views

Capacitor to Retract Solenoid with Low Voltage?

So what I'm basically trying to do is have a push-button motor with a solenoid to open when powered but then close and abruptly stop the gears of the motor from turning. The issue right now is that ...
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1answer
49 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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2answers
782 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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0answers
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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1answer
64 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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1answer
54 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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0answers
49 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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44 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
184 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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115 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 ...
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2answers
1k views

Can a novice safely splice in wire to lengthen 5V charging cable?

I have a 5V 1500 mA charging/power cord for a camera that was too short to reach the mounting position I need, so at the suggestion of my electrical engineer father, I decided to try to lengthen it. ...
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1answer
87 views

Can I use network cable for low voltage DC power?

I'm a guitar player with a crazy idea for a 2 part bypass looper: Enclosure A is just big enough to house 4 footswitches and an ethernet jack. Enclosure B has 9V DPDT relays to route audio ins and ...
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4answers
184 views

What can happen if 24vdc is applied to an Ethernet port?

We have a device with two RJ45 ports. One of these ports is for receiving 24vdc on pins 7(-) and 8(+) to power the device. The other RJ45 port is an Ethernet connection. The ports are of course ...
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1answer
72 views

Device for preventing 12V battery from dying

I am looking for a device which cuts off the connection between batteries and the system just like a circuit breaker when my 12V battery goes below 9V(for example) for preventing it from dying ...
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0answers
38 views

Responsible Battery Reserve Capacity and Low voltage?

It's been asked here, but looking for clarity. How bad is it to undervoltage a 12-volt lead-acid battery? SLI automotive starter batteries list RC (reserve capacity), but I think this a usable ...
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1answer
298 views

Digital voltage stabilizer relay diagram

I am using this voltage stabilizer relay diagram below, which provides a 16 step-up level. I need to edit it, so that I can made it to work as step-down in case of high voltages such as 245 and above. ...
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1answer
166 views

Stabilize circuit on 5V 2A

I have not yet build following circuit: Circuit in high performance needs 5V 1.7A (measured). I have source which is powerbank with 16 000 mAh. Outputting via ports: USB-C 5V/3A, USB-A 5V/3A, Micro-...
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3answers
213 views

Does the Rds(on) of a MOSFET vary based on source-drain voltage?

The Rds(on) of a MOSFET decreases when you apply higher gate voltage, but does it typically vary based on the source-drain voltage? I will be using a MOSFET to switch very low voltages (10's to 1000'...
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0answers
134 views

Electric heating for glass melting furnace

Some furnaces use electricity for glass melting. Low voltage and high amperage power is passed through the molten glass through 2 molybednum electrodes dipped into the glass. The molten glass acts as ...
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1answer
65 views

How to determine which harmonized standards are relevant to achieve CE conformity declaration

We are aiming to develop our first product to achieve a CE marking. So far i understand that there are a few directives like Low Voltage Directive (LVD), ROHS, EMC, etc, which can be implemented by ...
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4answers
609 views

Too High Voltage Drop across Transformer's Output

I want to get very high current flow thought secondary winding of transformer on my 3 Ohm load. As I apply high voltage of secondary to the load the voltage across it drops dramatically. Only about 2% ...
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1answer
103 views

Reducing the start-up voltage of a low voltage cut-off circuit

I just built this circuit, with the intent to use it as a low-voltage cut-off switch for a single li-ion cell. It works great, but once it's triggered it needs about 7 volts to turn back on, so I ...
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2answers
36 views

Pros and cons of centralised vs decentralised power deliver for small devices

How does compare using one power supply for multiple devices vs each device having its own - regarding efficiency eg. power consumption? Model situation: Home automation using low power devices such ...
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1answer
308 views

How to convert high voltage DC at low amps to low voltage DC or AC at high amps?

How to convert high voltage 500 volts DC at very low amps to lower voltage 12 volt DC or AC at high amps? Must I use an electrostatic motor or can I use an op amp? The reason I am posing this is a ...
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2answers
111 views

Cheap Low Power Signal Transmission To Smartphone

For my university project I'm making a certain sensor which has to (one-way) communicate with a smartphone. The sensor needs to be as cheap/simple as possible (aiming at +- €0,50 in total) and only ...
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2answers
625 views

3.3V overvoltage limiter circuit topology

I need to design, using discrete components only, a shunt voltage limiter that drains little or no current (less than 2mA, the lower is better) at 3.3V, and ensure that, when driven at more than 4V, ...
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4answers
166 views

Can I provide a constant charge to a battery?

I have a sketch here of what seems like a solid plan. sketch I need to provide a .2ohm coil around 3.7v which will take around 20 amps. The load will be very brief; 3-5 seconds, and intermittent; ...
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0answers
998 views

Low voltage cutoff circuit with PV panel

I'm trying to build a simple reliable low voltage cutoff circuit and sufficient voltage turn on circuit for a PV panel powered circuit. The idea was to supply power from PV panel to a working circuit ...
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1answer
70 views

Safety for 48v leds in water

I'm builing a 48v DC LED system to be used inside a fountain in a public space. I'm using a 48DC 30A switching power supply. What should I do to make it safe in case any conductor gets exposed to the ...
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2answers
772 views

Determining safe current and fuse rating for LV LED lighting

My home builder pre-pulled a length of 18-8 solid copper wire (18 AWG, 8 insulated conductors inside single jacket) into the ceiling of a room where I want to use some LED lighting with a remote power ...
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0answers
5k views

Smallest circuit for Ultrasonic Mist Maker or humidifier

I am working on Ultrasonic Mist Maker or humidifier circuit, but does not found any good circuit. As search on google that we have to make about frequency 1.6MHz to convert water into mist. using ...
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1answer
95 views

Safety Standards for Low Voltage Systems

I am looking for safety standards which could be applied to the piece of equipment desribed below. Basically the piece of equipment is a housing which inherits a 24V 100Wh Battery (2x SBS60) and a ...
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2answers
81 views

Logic level for system lower than IC's recommended logic level

My system has a logic-level and logic-supply-voltage of 2.4V. I want to use a particular IC in it (which basically operates as a shift register), and the datasheet says the minimum recommended logic ...