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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72 views

Chattering relay on microcontroller power supply

I am working with a device that has a relay on the 12v power supply to the micro controller that runs the device. Under certain unplanned circumstances this relay can chatter. What is the potential ...
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19 views

I am looking to isolate an inverter when power from a generator is applied- debounce relay?

I have tried to find specific info on this scenario with no luck The situation is this; Off grid power system 12v battery store runs 12v lights etc. and an inverter for things difficult to run or ...
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41 views

Relay is not isolating properly its sorrounding circuit blocks

It turns out I've been building up an elevator for a project (at College). In general terms, everything appeared to be correct, regardless that I hadn't simulated each part. I decided to begin with ...
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33 views

Relay circuit for AC application

I am using relay circuit for inverter application. It's 12V relay having coil and two contacts for connecting line and neutral respectively. But, I am not getting closed connection when I am giving ...
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2answers
46 views

Smartphone headset jack to relay [closed]

Looking to see if anyone has seen a relay triggered by a sound file played thru the phones headset. My idea is to connect an old smartphone to my home's WiFi and then connect it to my garage door ...
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2answers
59 views

How do I read this relay pinout/schematic?

I'm trying to understand the way this relay works. To me it looks like this KUHP-11DT1-12 is a DPDT relay. Pin 7 is connected to 1 or 4 and pin 9 is connected to 3 or 6 depending on whether the coil ...
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52 views

How do I protect digital design from EMI?

I have built a system that controls a 3 phase induction motor. Unfortunately I don't have schematics, but the system is simple: A 24V DC contactor switches AC to the motor. 24V is fed by a separate ...
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2answers
91 views

I want to operate a DC 9v relay with a small power

Can a lightbulb be switched on using two mobile phones? (Make a call and the bulb switches on) I need this for a kid's school project so the questions like should the bulb keep glowing after the ...
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1answer
80 views

Relay that detects 240VAC and switches 12V DC

I'm wishing to detect the loss of AC power (in this case 240V) and when this event occurs have a 12V DC circuit go to earth. This will trigger an alarm for users to react to situation. Can anyone ...
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57 views

Why solenoid valve when a liquid pump can be electronically controlled?

In some quick research online, I'm often seeing configurations where a liquid pump is used in tandem with a solenoid valve on the same liquid path. So, let's say I have a very simple scenario: a ...
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31 views

How does the impedance of the source effect the positive sequence impedance measurements of distance relays?

How does the impedance of the source effect the positive sequence measurements of distance relays in relation to power system protection? I wrote that increasing the source impedance decreases the ...
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2answers
75 views

Replace mechanical switch with transistor? MOSFET? Relay?

If I have a switch in some consumer electronics that I take apart, and want to replace a mechanical switch with a digitally controlled one, which component should I use? The only problem I see with ...
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2answers
148 views

Relay “sticking”

We are experiencing a problem where the mechanical switch of a SPST NO relay (COTO 9007-05-01) is not opening back up when the coil is de-energized. Current keeps flowing through the switch until we ...
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1answer
36 views

Issue getting relay to trigger, coil voltage might be insufficient

I have a simplisafe home alarm system. All components of the alarm(keypad, base station, sensors, alarm) are wireless, so there are no wires running to any sensors. I wanted to add an additional siren ...
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2answers
72 views

Problem with a relay

I'm quite new to the electronics, and I'm currently reading a book to learn it. In the chapter I'm in, the author is talking about relays, so I tried to make a simple circuit using a relay IM46. Here ...
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2answers
60 views

WiFi relay to DC motor

I'm trying to use a 12 volt WiFi relay setup to control a 12 volt DC motor. The WiFi relay has eight 10 A SPDT relays in it and the motor is 15 A. I understand how to wire it directly to the two ...
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58 views

High voltage low voltage switching circuit

I am working on a project which involves switching of a point from AC mains to low voltage ground when I start my low voltage circuit. Till now have come up with following circui. 1) Point A in the ...
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2answers
50 views

AVR main loop interference with relay

I'm working on a test program on an ATmega164A that toggles a 12V relay on and off (with no load) through a ULN2003A. For my test program, I'm toggling the relay at 100ms. I've got an IN4001 diode ...
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1answer
67 views

Contactor control circuit

I am trying to understand a contactor control circuit that I took apart from a broken GIGAVAC GX14BAB. Here is a list of parts that I think are the closest representation of what is on the PCB: ...
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1answer
68 views

Determining Voltage and DC/AC from Wiring Diagram for Spark Door Buzzer

I'm looking to use my Spark Core to control my door buzzer in my apartment. I'd like to identify the correct parts I need to build the required circuit, but this seems to be dependent on the voltage ...
2
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1answer
110 views

General wiring questions: high power LEDs, relay and microcontroller

I think I understand the Raspbery Pi GPIO pins and most of how this diagram below works, at a high level at least. First question, it's not clear to me exactly how the middle part with the ...
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35 views

Remotely Toggle Relay

A while back I decided I wanted to get into electronics, after which I bought a number of components to get me started, along with the Raspberry Pi and breadboard I already had. I am now wanting to do ...
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2answers
282 views

Why would I need a relay between a DC motor and my Arduino?

I was told that I should put a relay between my 5V motor and my Arduino. I asked why, but they didn’t know. Why do I need to separate them with a relay? The motor requires 5V and the Arduino provides ...
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69 views

Relays and Determining the State of the Relay

This is a set-up for switching our relay and determining the state of the relay. The problem is that if multiple loads (2 or more) are already connected in parallel, the load (which is a light bulb) ...
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2answers
109 views

Switch on computer with microcontroller

I'm making a simple microcontroller based circuit to turn on a computer when certain events are triggered. I am interfacing it using the PCs soft power switch pins on the front panel header: There ...
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1answer
46 views

Equivalent sequence/stepper relay to “FINDER - 20.21.9.012.4000”

I am currently looking at this relay: FINDER - 20.21.9.012.4000. Which is step relay, that makes contact AC output active with coil input DC (12V) [which i need]; and disconnects output when coil is ...
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42 views

Finding low-contact resistance relays

I'm trying to find relays with low (<5 mOhm) contact resistance, or ON-resistance. It doesn't seem to be something that's universally specified, and when it is, it seems to always be something like ...
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1answer
42 views

Trigger Relay Only from one specific grounding path?

I have a car wireless door lock system I want to modify. The basic operation is that when the key fob's button is pressed, a light relay is triggered, to flash some of the car's lights, to indicate ...
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1answer
406 views

Is there such a thing as a pulse relay?

Is there such a thing as a pulse relay? So that I do not have to supply constant power for it to remain open, instead just pulse it?
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105 views

How to protect FPGA from relays?

I'm preparing for a project that will interface an FPGA with many 3v relays on its gpio. Additionally, some of the relays will be powered with the same power supply that the FPGA uses. The FPGA will ...
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1answer
184 views

Arduino crashes switching 230V relay OFF

Here is my circuit schematic : I need to power ON/OFF a 230VAC fan using a relay. The relay is powered by a 5V DC power supply. Digital pin on the Arduino board open or close the circuit in PNP as ...
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3answers
56 views

Two sequences in order, one button push

I am inexperienced in the field of electronics and don't yet understand diagrams and things alike, but I have a specific need and would appreciate any help you can provide. I am constructing a ...
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3answers
193 views

Where to put freewheeling diode in relay circuit?

I am building a circuit to lock/unlock a door using a standard electromagnetic door lock (http://www.amazon.com/Seco-Larm-E-941SA-600-Enforcer-Electromagnetic-Holding/dp/B00196YB5Y) and controlling it ...
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3answers
147 views

How do Wi-Fi controlled light switches feed themselves?

There are smart light switches in the market that are Wi-Fi controlled like Plumlife (formerly ube) and Belkin WeMo. I wonder how they control the electricity that they operate on. When I unplug my ...
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89 views

Why doesn't this relay circuit work?

Objective: A device to prevent automatic restart of a motor (or pump) after power failure. Background: It is well known that aquarium fish are curious and will explore items in the tank. In the ...
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1answer
59 views

Driving a linear actuator from a home automation system

I am not exactly an expert into electrical engineering. I have a Linak LA12 IC linear actuator, and am trying to drive the motor from two outputs on my home automation system. The home automation ...
2
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1answer
154 views

How to detect that my apartment door buzzer is being pressed

I want to detect the button presses of my apartment's door buzzer. This is the button in the building lobby which, when pressed, plays a ringing/door bell sound in my apartment to alert me that ...
1
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1answer
118 views

How to supply 2 different voltages to a circuit every 2 minutes

For executing a (stress) test scenario, I need to simulate the following behavior on my circuit: for 2 minutes, deliver 11V to the circuit for 2 minutes, deliver 14V to the circuit for 2 minutes, ...
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2answers
137 views

Turn on an LED when power is lost with a relay

A friend of mine has just finished his race car but is having fan issues. What I want to help him do is setup an LED that turns on when the fans have lost power. Often the fuse blows. I would assume ...
0
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1answer
59 views

Raspberry Pi high voltage supply soft-off circuit

After looking at various designs for a "software" controllable power off circuit for a Raspberry Pi computer I decided none of them fit my need so I designed my own. Before I commit it to a PCB for ...
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4answers
215 views

How do I get a digital signal from a switch?

I want to essentially drive a relay using a switch. For eg: If the switch (AC Voltage : 220v, 50Hz) is switched on, it sends a digital signal to the relay to switch off.
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2answers
314 views

limit switches to control motor direction

I am trying to use two limit switches and two DPDT relays to control the direction of the motor. When the power is applied the motor should rotate one direction (direction for this question isn't ...
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2answers
182 views

Two relays for DRL on a car

I am trying to make a circuit for my newly installed DRL (Day running lights), what I am trying to do is have the DRL run all the time, turn off when using high beam, dimmed when headlights are on. I ...
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0answers
76 views

Insufficient Power when using one power source vs two [duplicate]

So I've been working on a wireless remote relay switch using several components and have struck a break wall. The issue I'm having is that the D0 siginal output triggers the relay but only at short ...
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1answer
195 views

Control relay from Bluetooth on ATtiny85

I know someone else has made a Bluetooth transmitter to a relay so i wanted to ask a few questions about it being possible? I am an almost newbie at electronics but i do know a few things, so first of ...
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1answer
90 views

How to increase current output of a multiplexer for activating a relay

I want to make a multiplexer for my project which needs 24v dc to operate. I am using an OR Gate IC for generating an output. My 4 gate inputs are connected to 6V battery power and I am getting a 6V ...
0
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1answer
89 views

How can I amplify cellphone's vibrator signal to switch my home electricity on or off?

I need to connect my Samsung s1 cellphone to my home's lights when I am away. I realised that I can use my cellphones' vibrator signal when I call my "Home" cellphone number. I know that the mentioned ...
2
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1answer
77 views

voltage regulators destroyed — protection diode needed?

I have the following basic circuit: As I was flipping the button to turn the relay on and off, I noticed sparking from the voltage meter, and it eventually caught fire, releasing the magic smoke ...
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2answers
90 views

How do I active the relays on this relay bank?

I purchased 2 "Mechanical Relay Board, 8 gang, 10A 220VAC, 24VAC 30ma coil" relay banks that I am trying to control from a raspberry Pi. To do this I've built out 2 595 shift registers and I'm using ...
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1answer
118 views

Minimum permissable load for a relay

I understand the purpose of the minimum permissible load (for contact wetting) but I want to know the relationship between the voltage and the current. For instance, the above table states that the ...