Tagged Questions

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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1answer
79 views

Circuit seems to lack something

http://www.electronicecircuits.com/electronic-circuits/cd4060-timer-circuit-1-minute-to-2-hours I've replicated the circuit in the given link but \$D_2\$ in my circuit doesn't work at all. Also, the ...
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2answers
39 views

Using DPST Relay to control AC Load

Below is the functional schematic that I am planning to use to control an AC load (air conditioner in this example with max current draw of 32A). Since I am still relatively new to mains power and ...
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1answer
37 views

Mains into a relay?

Will hot/live go into NO and neutral into COM, to switch over 200v? Can someone explain please. I saw in some places it says natural into NO but what into com?
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61 views

Relay voltage drop, a solution?

I simulated an H bridge with 2 relays and one motor in PROTEUS. Everything is 12 V and DC, I set relay coil resistance at 80 ohm ( I am replicating this : ...
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30 views

Mounting SSR + HEATSINK

I have made a AVR based Bluetooth mains controller. The idea is to be able to control my AC using my phone. Since I would be controlling an AC, I figured I would be needing a solid state relay with ...
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0answers
39 views

Ultrasonic welder is arcing [on hold]

I have a ultra sonic automated machine that keeps over loading and is blowing cube relays. The welder genarates alot of heat also. Is there anyway to find out why my machine is feeding back into the ...
2
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1answer
46 views

Using a MOSFET or BJT instead of solenoid

I'm trying to convert all relays and solenoids to transistors in a circuit to make it solid state. I have a small (150cc) 12V DC starter motor that is currently turned on by a small transistor turning ...
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1answer
47 views

I need 2 vcc pins on the arduino?

I need to connect the vcc pin to a bluetooth module but then I need to sue it again for a relay module what do I do?
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14 views

How can I control an IR204E in a PK543A to remotely operate this apartment door buzzer? (What relay do I need?)

My apartment door 'suite station' (buzzer) is a TekTone IR204E (pdf). It has an option for talk, listen, and open door. It contains four wires labeled 1, 2, 3, and X. My research leads me to believe ...
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39 views

How to control a bulb operating on 230v using a switch operated at 5v

Hello Electrical engineering community, Maybe this is an easy question to answer but I am new to this so definitely need assistance. I want to control a bulb which is driven via 230v AC mains using ...
0
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1answer
40 views

Running a load off a solar panel connected to 2x 12V batteries.

I am having trouble figuring out what relay I should be using for my solar panel set up. I have a solar panel running to a solar charge controller. I then have the controller running into a relay. ...
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2answers
203 views

Circuit Protection re: Relay Coil

Is the flyback diode adequate protection in for the microcontroller in the following circuit? simulate this circuit – Schematic created using CircuitLab Will my circuit experience over ...
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1answer
77 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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1answer
20 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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0answers
42 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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2answers
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
48 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
62 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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0answers
54 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
98 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 ...
0
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1answer
82 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 ...
0
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1answer
59 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
82 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 ...
2
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2answers
150 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 ...
2
votes
1answer
43 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
65 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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0answers
63 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
70 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 ...
2
votes
1answer
72 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: ...
0
votes
1answer
71 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
votes
1answer
113 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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37 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
289 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 ...
0
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0answers
71 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) ...
3
votes
2answers
113 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 ...
0
votes
1answer
48 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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0answers
44 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 ...
1
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1answer
45 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 ...
2
votes
1answer
407 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?
1
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2answers
106 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 ...
1
vote
1answer
204 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 ...
0
votes
3answers
60 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 ...
1
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3answers
202 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 ...
2
votes
3answers
154 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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91 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 ...
1
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1answer
60 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
votes
1answer
161 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
vote
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, ...