Electrical Engineering

Questions tagged [relay]

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A relay is an electrically controlled switch. Electromechanical relays use an electromagnet to activate mechanical contacts, solid-state relays use semiconductor switches.

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Universal series motor control using relays

I have a 220AC universal series wound motor I am trying to connect to a RF Remote Switch using relays and full bridge rectifiers. I have come up with the following schematic: The RF Remote Switch ...
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I can’t remember the name of that component

I’m looking for the name of the component that act like a relay but instead of using a coil to generate a magnetic field that moves the relay « arm » it uses a LED and a photosensor. It allows to ...
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64 views

Explanation of structure and function of a safety relay

I am reading a safety guide from Pilz. This guide contain a chapter about safety relays. A circuit given in this guide is given below: I know the purpose of all switches and buttons defined in it. ...
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Is this design feasible? Door-open warning light circuit with safety interlock switch and general SPDT relay on wall voltage (120VAC)

I am trying to design a very simple system for my workplace that turns on a warning beacon light when a swinging door is opened. My current thinking is to use a non-contact magnetic safety interlock ...
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1answer
33 views

Thermador oven circuit board troubleshooting - where to go from here?

I have a Thermador double oven unit that is not working correctly in one of its cooking modes. I have done some troubleshooting, but haven’t located the problem to my satisfaction. I wanted to see if ...
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35 views

Controlling a 5V power supply with a 5V signal

The might sound like a dumb need. Why if I have a 5V control signal would I want to control a 5V load? The issue I am up against is a voltage drop over a long run. In a home automation setup the ...
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Can relays and a switching regulator chip be placed side by side on a PCB for EMI reduction reasons?

I'm designing a PCB. I'm looking for the best way to place the components with maximum EMI reduction and minimizing the dimensions of the PCB. How should I place the relays and switching regulator on ...
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41 views

How to troubleshoot low-voltage home lighting system from 50s

My home, built in the 50s, has a Sierra low-voltage lighting system, where low-voltage 24DC switches control relays that power the normal 120AC lights. In the last week, the switches have failed ...
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49 views

Relay contact ratings

I am looking at this relay part: FTR-LYCA012Y. I am tasked with finding a relay part with contact ratings of 5A for both 250Vac and 30Vdc, even better when UL approved. The datasheet has a table at ...
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2answers
39 views

Help wiring relay to LED driver - L/N on driver to L/O on relay?

I have a Shelly Dimmer 2 wifi-controlled relay, and I'm a bit confused as to wiring it to my LED module. The front of the relay looks like this: This is the LED lamp I am trying to connect. At one ...
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65 views

Relay with built in manual switch

I have a question regarding the manual type relay switch shown in the picture. I need relay with dual coil-latching, I thought of using avmomentary toggle SPDT to turn the relay on and off, but I will ...
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37 views

How to drive a relay from a MOSFET/IRF?

simulate this circuit – Schematic created using CircuitLab Hello, I would drive a machine to pilot its ON/OFF status. So in idea it should be OK but is it? What requires attention or this is an ...
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5V relay not disengaging [closed]

So, I'm trying to add a relay to my printer for remote power on/off. I wired it up yesterday and it was working fine, but it was getting quite late so I didn't end up putting all the cables back to ...
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3answers
47 views

Relay coil set and reset with momentary switch

I am having trouble with the activation of a set-and-reset coil of a relay which is dual coil-latching. The datasheet mentions that to set or reset the coil I need to apply the rated voltage for max. ...
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40 views

Arduino resetting or malfunctioning when controlling 48V DC motors with relay module

I'm building an Arduino controlled crane machine out of old crane machine parts. The motors in a crane machine are 48V DC and I am controlling them with an H-bridge configuration using an 8 channel ...
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32 views

Difference between a DC SSR (solid state relay) and AC SSR

I am trying to understand the difference between a DC and AC solid state relay. For electromechanical relays, I notice that they are often rated for some VAC load and a smaller DC load. Solid state ...
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20 views

Switch to activate backup circuit

I am designing a device that will use a small heating element. The client initially designed it to use an incandescent bulb as a heat source. I want to maintain that as a back-up which will not only ...
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35 views

Impulse relay functionality without latching

Let me start by declaring that I have absolutely no idea what I'm doing so please try to keep it simple if possible. Thanks in advance. I have a project requirement that uses simultaneous input from ...
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38 views

how can i switch one light bulb with two power source with relay?

I am making and project in which i take two inverters and connect with light source with the help of relay. I'm Planning to switch between two power sources with a Arduino like below diagram.So if one ...
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2answers
45 views

Trying to understand relay power limits (strictly for DC)

Let's say I had three batteries in series with two SPDT relays such that the circuit goes relay1->battery1->relay2->battery2->relay3->battery3->output, such that the relays either ...
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2answers
68 views

Power 12v DC actuator when 120v @15 amp saw is switched on

Problem: I want to use a 12v DC actuator to close a blast gate on my dust collecting system when I turn on a 120v 15 amp saw. The actuator can only run for a few seconds until the 6" stroke is ...
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3answers
58 views

Controlling AC Motor with Relays

How can one control on/off and direction for a single phase reversing AC motor using relays? I have wired an AC motor correctly with 5 wires: green (ground), red (live), black (neutral), blue (coil 1),...
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1answer
28 views

Solid State Relay in NC configuration

Is it possible to build an SSR relay circuit for controlling 240VAC (using TRIAC and other components) with NC configuration? The idea is to keep the AC circuit closed, even when there are failures in ...
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42 views

Correct way to wire a 5V relay using BC547

i am trying a relay circuit. I saw one diagram online in google images and another one when i actually test. Here are the two diagrams: Diagram 1 This one i tried but not worked for me. But its a ...
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Are there a way to join 2 I/O control lines using staircase two ways switches approach?

I am a newbie and would like to have a question and would like to have your advice. Requirements: Control 1 relay (max current is 20mA) over 1 Arduino pin (pinMode as OUTPUT and state of this pin is ...
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23 views

Switching a relay with an Arduino using a transistor and an optocoupler

I want to switch a relay with an Arduino. The Arduino runs on 5V though, while the relay needs 12V. I want to use this circuit: Will this work and what transistor and optocoupler do i need to use?
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51 views

Raspberry Pi relay on GPIO does not toggle, but does on +3V power

I am trying to toggle an SRD-03VDC-SL-C (3V rated) relay with a Raspberry Pi GPIO. When I put a wire to the Raspberry Pi 2B ground pin and the other to a 3.3V power pin the relay works (it clicks). I ...
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32 views

How should I connect the RX and TX pins of an Arduino to a Bluetooth module?

I am working on an Arduino based Bluetooth controlled home automation using a mobile app. When I power ON the circuit, it works fine but when I power it OFF and power it ON again I have to remove the ...
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95 views

Sound operated relay

I am new to electronics and I can't get this simple circuit to work. Can anyone please tell me if the circuit is drawn correctly and the values are right? It is supposed to run on 5 to 12 volt. I am ...
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1answer
71 views

FET DC operation in the ohmic region if the SOA curve doesn't have a DC line?

From my understanding, the SOA lists the drain current for a given VDS in the ohmic and saturation regions where the FET can function without damage. I read a thread that says FET SOA graphs with ...
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2answers
215 views

3.5mm audio jack to trigger 5V relay

I am pretty new to electrical engineering, so please bear with me. I am trying to activate a 5V relay when it detects sound coming through a 3.5mm jack. Can anyone help me figure out how to do this?
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49 views

Turning a circuit off using a 240v signal

I have a home-built controller for a HERMS brewing system (Heat Exchanging Recirculating Mash System). The purpose of this controller is to drive liquid (wort) from a large mashing vessel (a cooler ...
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1answer
53 views

Relay switches to ON/OFF rapidly

I have this relay circuit that can be turned ON/OFF by NodeMCU ESP32 GPIO18. This circuit allows current to pass through the RL2 even when NodeMCU is turned off. When GPIO18 is HIGH, it will switch ...
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2answers
60 views

Is it possible to make a one-off control FET switch circuit?

I was wondering if anyone knew any circuits such that when a small voltage is applied for a short duration (i.e. 500 ms), a switch transitions from the off-state to the on-state or vice versa for all ...
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1answer
63 views

Relay Continuous Current Ratings vs Size

This is my first post. I have been coming here for years though. I am designing a relay board for my motorcycle to control power to various accessories - lights, heated gear, horn, GPS, etc. It's a ...
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1answer
52 views

Looking for solid state switch

I'm looking for a switch like element. I want to use it with DC, but intend to use it to charge and discharge a capacitor. A triac would seemingly be perfect, however, I did a bunch of LTSpice ...
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2answers
24 views

What is the power requirement for switching this relay?

I bought a heavy duty relay to control fluid pumps. I'll have a 12VDC power source to operate the pumps and I bought the following relay board to control them using an Arduino or other type of board. ...
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2answers
72 views

Controlling AC relay with a single push button?

Is it possible to set an AC relay (220vac coil) ON / OFF by using a single push button (non latching) and some extra components but without the need of an additional DC supply? It doesn't have to ...
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1answer
32 views

Magnetic float switch + relay setup to control a water pump

I have a question regarding connecting a Standard magnetic float switch with a relay to control a waterpump. Relay being used is RM22LG11MR from Schneider with datasheet here My setup looks like as ...
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23 views

Modular synth clock and sequencer control by relay

My modular synth master clock and sequencer don't communicate well. The need to have reset trigger for the sequencer has forced me to come up with a module that can send a control voltage to the clock'...
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1answer
55 views

Explanation of DPDT Relay circuit (Used as SPDT) for cutoff

I need help explaining how this circuit works and what the purpose of each components is. This circuit was used in my semester project and I want to be able to understand and explain it. Thanks in ...
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29 views

Is MOSFET Drain Source resistance always affected by Drain Source Current? Is there an IC which is not?

Im trying to measure the voltage of a variable resistor in a voltage divider setup, where the current for the voltage divider is sourced and sunk through a pair of MOSFETS. I assumed that Rdson (drain ...
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1answer
93 views

how to control 80 outputs using 1 plc?

i am new PLCs. i'm currently working on a project which requires me to control 80 outputs (small pumps) with 1 PLC. can anyone tell me if this is possible? do i need 80 inputs to control each one ...
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1answer
75 views

Voltage/Current rating of Relay for Inductive load

I selected a relay for my application by seeing the maximum and current rating of Relays but I am confused if the relays works fine with the given rating for all kind of loads. In my circuit the relay ...
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2answers
36 views

Lowest power circuit to control low current 240v circuit

I'm trying to control 6 normally-closed 230v valves using a raspberry pi. These valves draw little current when energised (1W) but do have a maximum inrush current of 550mA. Normally this would be ...
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25 views

Improve Mechanical Switch Reliability

Currently I use a USB-6501 DIO and inexpensive Sansmart 8x1 SPDT relays to switch on/off numerous inexpensive fixed DC power supplies for a flash programming process. Every 20,000 to 50,000 parts i ...
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1answer
54 views

Connection for 11,12 and 14 in the relay based water pump setup

I have a question regarding a relay based water pump setup which is triggered by a float sensor in the water tank. As you can see in the figure, I have two relays which are single phase AC. Both ...
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38 views

How to open two circuits using one input?

I'm not too familiar with circuits so was wondering if someone could help out with this. I have two separate loops with a source and load each as seen in the diagram. I want to use one set of temp ...
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1answer
83 views

STM32 12v relay driver circuit

I spent the day looking for a circuit driver to control a 12V Omron G4A (rated current 75mA@12v) relay with 3.3v GPIO of STM32, without success. According to my calculations the circuit below should ...
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50 views

MCP3561 Configuration registers resetting upon relay activation

I am looking for advice on how to solve a problem I'm encountering with my PCB project. The application involves reading a weight from a cluster of load cells and activating a relay that controls a ...

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