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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38 views

thyratrons or vacuum tubes for relay control

I am trying to build a tube amp without using any semiconductors (just for the fun of it, trying to make it using the technology that was available when tube amps were mainstream). I may need to ...
0
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0answers
21 views

how would I develop a circuit/design for the control of the flow of execution using electromagnetic relays?

I am working on designs for a relay-based device. It includes a binary adder with inputs numbers A and B, and output number Q. Memory is implemented using latching relays, and addressed with a ...
0
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0answers
16 views

Beginner needs help - Rpi controlled lights question

Im currently working on a home automation project and ive came across a roadblock and hopefully someone can tell me if what i want to do is possible and maybe point me to the right direction. This ...
0
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1answer
25 views

Simultaneous operation of inverter and diesel generator in a solar system

I have a problem at one of my on-grid solar system project. There is a problem which lets the solar inverter on, when the grid is off and the diesel generator is on. As you know that, the solar ...
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2answers
93 views

Designing PCB with Multiple power supplies

This is my first REAL project and i need some help. I'm working on a project where I am trying to design a PCB for controlling the environment inside an enclosed cabinet to grow a tomato plant using ...
0
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1answer
42 views

Construct a relay circuit?

I need to construct a circuit with 4 relays that implements the functions $$f = xy+x'y'$$ and $$g = x'y + xy'.$$ I know that x'y + xy' = (x + y)(x'+y'), but does this help?
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2answers
47 views

Inductance of a relay coil

I'm using a magnetic latching dpdt relay from Teledyne company. The value of inductance for the coil in the relay is needed and not given in the data sheet. The part number of relay is 422d from ...
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0answers
12 views

Confirming the use of a RIFA snubbing component across 120V relay switch

I have a mains relay switch (Packard C230B 2 Pole 30 Amp Contactor 120 Volt Coil) which allows me to turn on my pre-amp based on the existence of AC voltage on the amplifiers AC output plug (which is ...
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2answers
33 views

Can a malfunctioning relay in an amp cause or allow a speaker to crackle when turning the vol potentiometer? [closed]

Ok, so this question has several layers, I admit it. I recently acquired a Lepai 2020A+ amp. It is, I believe, the latest version PCB because it has the two relays for speaker protection instead of ...
0
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0answers
19 views

Measurement of 230VAC relay noise

I have an MCU which is switching a load, which is connected to 230VAC via a two pole relay switching live and neutral. The load is another MCU board with its own ACDC. My problem is that when the ...
-1
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1answer
43 views

Detect open or closed circuit via USB sensor

I have a relay which I need to detect the state of (similar to this question but no current flow) and would like know what the easiest method would be to detect the state via USB and Raspberry-pi. I ...
0
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0answers
29 views

how to reverse polarity with a timer 120v

I have a 120v electrically actuated ball valve that I am trying to control with a timer, so that it will not open at night. The ball valve needs a small amount if power for a heater to prevent ...
1
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1answer
37 views

Sanity check my first project: to control my air conditioner with a Nest

I have a window air conditioner. It works well but is a bit old — new enough to be electronic, have a remote and a digital display, but not new enough to turn on from my phone or do anything smart ...
0
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1answer
39 views

Drive relay with Npn transistor thanks to RTC and Rpi

It' s my first projet in electrical and i m not very sure about what i'm doing ... I Would like to drive a relay thanks to a Rpi and a RTC clock that has a alarm feature ( ds3231 with high-z/active ...
0
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1answer
41 views

How can I relay 120VAC with a raspberry pi?

I have five 75W 120V AC LED lamps on a dimmer switch. They draw 13 watts each (375W total). I also have a 600W Lutron dimmer switch hooked up but the thing buzzes when the lights are dimmed. I also ...
0
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3answers
38 views

Kn2222A darlington pair + a relay, not functioning at low currents

As the title explains it, I have Kn2222A x2 transistors connected as a Darlington pair connected at the ground side of a [JQC-3F (T73) 5v] relay The relay is connected to a 5v power supply. the ...
0
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1answer
73 views

Distortion in ADC output

I am working on Intel Galileo board and using its one ADC pin (A5) and one digital GPIO pin (pin 8). I am switching a relay from GPIO pin and using ULN2003A for isolation and LM60 temperature sensor ...
0
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1answer
75 views

Do we have a SSR relay technology that can stand 100 switching per second for a long time?

Are SSR relays capable of switching on/off 100 times per second for a long time? For example 1 hour? Does this affect the longevity!? I want to use relays for 5vdc control and 12vdc output with very ...
9
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4answers
826 views

Are relays reliable for long time use?

I am developing a home automation project in which I'm using relays to control appliances. I need to control devices with 220V and 6A rating. Should I use relays to control these appliances as a ...
1
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1answer
90 views

Why does this Relay not oscilate

I have built the above circuit. The relay switches once, but then stops. Why does this not oscillate, as the current is broken every time it connects?
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1answer
58 views

How to MOSFET to drive 12v relay from microcontroller (logic high is 3.3V) using ZXMS6004FF

The above is part of my project design. 'BRAKE_CTL_3' is output pin from uController. It sends 0 or 1 to drive Q4 to turn it on or off. 'BRAKE_LSD_3' connect to one end of Relay. Other end of relay ...
0
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1answer
46 views

Ground trigger on relay

I have been doing this for years (on automotive projects) but the need finally arose to clarify: When using a SPDT 12V relay (with internal flyback diode), should I isolate the ground trigger when ...
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1answer
106 views

Burning out relays when supposed to be within ratings

I am using this Normally Closed Relay on a 24V circuit: DataSheet The circuit is 24VDC source, which I measured the Amperage in series to be 29mA at the highest. I've breadboarded a lower voltage ...
0
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1answer
128 views

How to share a VCC and a GND across to multiple relays

I'm working on my first electronics/Arduino project to control two pairs of motors. Currently, the motors are controlled by a simple four-button, wired remote controller, where each button controls a ...
0
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1answer
73 views

Who triggers transistors to become H/L?

Admittedly that's quite a beginner question: When I learned that transistors work like relays and produce the digital values 0 and 1 what I always asked myself was: they have to be triggered by ...
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1answer
76 views

How do I energize a 12v relay coil using a 2N2222 bipolar transistor?

I'm relatively new to working with transistors, and I'm having some trouble getting this circuit to work. I want to use an Arduino's I/O pins (5V out) to energize a 12V relay coil. To do this, I'm ...
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1answer
26 views

Relay Contact protection of inductive load and maintain electrical isolation

I've been reading Henry Ott's Electromagnetic Compatibility Engineering and one of the chapters is about contact protection. Looking at the various protection mechanisms to prevent or minimize arcing ...
0
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1answer
25 views

Need to add blinker module to relay trigger

simulate this circuit – Schematic created using CircuitLab I have a simple light controller box. I have a 2 channel relay that controls a red and green light by magnetic switch. so we can ...
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1answer
46 views

microcontroller to drive relay using uln 2003a [closed]

I am getting around 2v from microcontroller port and I am using uln2003a to drive the relay. is 2v from microcontroller is enough to switch on the relay using relay driver. if not what should I use to ...
0
votes
1answer
41 views

Transistor based relay driver for DC motor is not working with 12V-8A DC motor?

I am trying to run a 12V-8A DC motor from pic microcontroller output pin via relays(28V-30A output rating). It only starts for a split second and stops. Where as small DC motor runs perfectly on the ...
0
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0answers
35 views

Mechanical Relay Alternative for Switch 15A at 120VAC

I'm using 2 of these relays in a design, K10P-11D55-12 (http://www.digikey.com/product-detail/en/K10P-11D55-12/PB327-ND/254544). They're really the only ones that suit my needs but they're pretty ...
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0answers
28 views

Recommendation for proper relay to trigger wired doorbell with wireless intercom

I was just searching my question and found someone on here recently asked this question: I am looking to do exactly the OPPOSITE of this. I would like to use the pushbutton of a wireless ...
0
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1answer
63 views

Replacing a relay with transistors in this step down circuit

I've made a simple circuit to step down voltage from 12V+ to around 5V, and while it works, it is noisy and it requires much capacitance. I would prefer to make it using transistors instead of relays. ...
0
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1answer
36 views

ic relay.. is there any delay for the responz of <İC insıde the circuit

Regarding SPDT ic relay TS5A3157. Do we have a delay responz inside the İc/ do we have a click sound. Because im startıng for a new project that can switch wireless, bluetooth or ir. What i need on my ...
0
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1answer
42 views

What kind of relay do I need for for 12V source with a 5V control voltage

Trying to figure out which relay I need for a project I'm working on. The source is a 12V battery, and I'm looking to turn on a 12v solenoid using a relay. I want the control voltage on the rely to be ...
0
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1answer
33 views

What is the name of contractors designing high power supplies with relay logic? [closed]

I have been designing a 3 phase power supply with distribution strip and redundant contactors with failure detection (I posted a question not long ago related to that, it's based on relay logic), and ...
5
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3answers
526 views

What is the difference between a solid state relay and a transistor?

Along with the difference between a solid state relay and a transistor, I'm also interested to know if there are transistors that act a lot like the typical relay modules you can find on ebay (where ...
0
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2answers
53 views

Latching switch turning back to off on power loss

I can't twist my head around the proper use of my latching switch problem. In detail, the latching (or maintained) switch should switch a 48V DC source power supply for a cisco router. The 48VDC power ...
0
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3answers
70 views

AVR single coil latching relay

I need to control several 5V single coil latching relays. The specific part has a coil current of ~20mA. The ATMega's datasheet claims a maximum pin current of 40mA. Is there a reason I cannot simply ...
2
votes
1answer
74 views

Meaning of AC15, DC1, AC1, and DC13 in relay durability curves

In the datasheet of the relay OMRO G7SA from the durability curve they specify the number of operations as a function of the contact current. Each curve is for a specific current and voltage. The ...
1
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1answer
87 views

Resistor instead of flyback diode

I was looking at the data sheet of a common 12v relay and noticed it mentioned using a resistor instead of a flyback diode for circuit protection. On the last page for 12V models it reads; When ...
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2answers
440 views

LED emergency lighting - relay activated

I've designed the following schematic for my LED emergency lighting project; I'm planning on building it soon, my knowledge in electronics is short right now (I started learning electronics by ...
0
votes
1answer
28 views

Question about the operation of a zener for a rapid relay release

This is a follow up question to Zener voltage selection for relay?. The following image was taken from the previous question I'm trying to grasp exactly what is happening in this circuit. My ...
0
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1answer
39 views

Zener voltage selection for relay?

This question is similar to Zener Diode Selection for Relay but the focus is in how to select the voltage for optimum or near optimum release time. With the circuit below, how does one select the ...
0
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0answers
68 views

Transistor switch help

For starters this is the circuit I have made. I don't have the same relay board, but it is active low. My problem is it seems my PN2222a transistor seems to be leaking current when the base signal ...
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0answers
62 views

Interleave two analog signals

I am trying to interleave two similar but not identical pass-band (analog) signals (i.e., both have a center frequency of 15 MHz, and a bandwidth of 200 kHz) on a sample by sample basis. The idea is ...
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45 views

Why do some Arduino relay modules can handle up to 250 VAC but not above 30 VDC? [duplicate]

When you look for "Arduino relay module"s, you usually see one form "SONGLE" that says on it: 10A 250 VAC 10A 125 VAC 10A 30 VDC 10A 28 VDC My ...
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2answers
220 views

Make-Before-Break Relay with Very High Continuous DC Current

I need to use a relay in order to do field sweeps with my electromagnet, which is hooked up to a couple very beefy monopolor power supply. (My magnet's impedance is ~2 Ohm, and I am putting ~40 Amps ...
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2answers
162 views

Java/Arduino Controlled 120VAC Power Outlet

I'm working on a project with an end goal of controlling a power outlet with a Java program. Currently, I have the relay wired to outlets, a 3 prong 120 VAC plug, and my Arduino. Everything works as ...
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0answers
17 views

eth008 relay pulse setup on phone app

Is there a way to set up relay pulse times for the Android/iPhone "Devantech" app when using ETH008 board? I noticed that it is possible using the test program on PC, but not possible on the app OR: ...