A solid-state relay (SSR) is a switching device that accepts a small control signal to control a larger load current and/or voltage. In many ways they perform the same function as an electromechanical relay without any moving parts, they have many advantages but also some disadvantages compared to a ...

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30 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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3answers
494 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 ...
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1answer
85 views

Microwave Oven: Switching Magnetron (Transformer) with SSR [closed]

I've got a used microwave oven and want to improve it with a digital user interface. Is it ok to switch the magnetron (more precisely: the transformer from 230V 50Hz to some kV followed by a diode ...
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0answers
57 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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2answers
63 views

Can Solid State Relays be used “anywhere”?

With mechanical relays, they can be inserted anywhere in a circuit. Can SSRs be used anywhere in a circuit or are there certain gotchas that exist ? Consider this simple example where SW* is a SPST ...
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1answer
61 views

Is this SSR design recommended?

I want a hard power switch for some battery-powered BLDC motors, but the currents (5A, up to 20A transients) and voltages (up to 60V) limit the kinds of switches I can use. Because I want some small ...
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2answers
60 views

How to use a solid state relay in a dip package to drive a 24 vac relay

We have a fan coil unit in our server room where I work that utilizes a microcontroller to control temperature and humidity. I have an HVAC and electrical background so I am familiar with ...
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0answers
38 views

Solid state relay (optocoupled triac) is extraordinarily hot when on

I am using the following part: 3-32VDC input to 240VAC max 40A, KD20C40AX, that is connected to an Arduino Uno that drives a 5V control signal to the opto. The application, (output/triac side), is ...
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1answer
57 views

Solid state or Mechanical relay

I need to control a load that uses 20A at 110v. Should I use solid state or mechanical relay? Mechanical relay's contacts can lose conductivity over time due to high current and high voltage, I am ...
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1answer
53 views

Is there any way to use an ac load ssr with a dc load

i have a s202s01 relay that i want to connect to my microcontroller. The problem is that the load i want to control is a DC source. Is there any way to make that ssr (3-24dc, 8A 250VAC) work with a ...
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3answers
38 views

Guitar pickup / PhotoMOS off-state leak

Brand new member here. I'm using an AQY211EH PhotoMOS relay to switch guitar pickups via an Arduino, as shown below: This works great, with one minor exception: even when no power is applied to ...
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50 views

Low cost solutions for reversing 130VDC 20A motor

I have a treadmill motor controlled by an MC-60 controller board. The motor is reversible and I want to control the direction using an Arduino. The catch is that it's 130VDC and 17A (the voltage ...
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1answer
87 views

Connecting SSR relay

I bought a cheap SSR relay (SSR-40DA) on ebay and like to connect it directly to arduino, Schematic on website (http://www.fotek.com.hk/solid/SSR-1.htm) shows that LEDs already have resistors in the ...
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1answer
33 views

What should a ture RMS Voltage meter read on the load side of a zero fire SCR?

I have a 3 phase zero fire SCR/SSR set that has 480V input. I put my Fluke 289 (which is a tRMS meter) across the different phases on the load side. Then adjusted the output. The voltage read ~470V ...
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2answers
70 views

Possible solutions instead of 12 relays

First of all i am new to electronics, but have some basic idea. I want to create a USB switcher with arduino, which will control "where" the usb device is plugged in, instead of unplugging and ...
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2answers
160 views

Need circuit to Switch 240v a.c. mains with 3v or 5v

I have the IRFP460 power transistor which if I understand correctly can switch 20A/500V on 20v input. I am wondering what a circuit design would look like that would allow me to either (a) switch ...
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1answer
46 views

Fuse and AWG choice for immersion heater circuit

I am planning to operate a 1500 W resistance immersion heater with an SSR and I'm trying to determine which fuse and AWG wire to use. The 1500 W heater on 115 VAC should operate at a current of around ...
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1answer
120 views

Using two Mosfets for AC

Im having trouble getting my head around using two mosfets to pass AC. I have reduced my schematic to its bare bones to help keep it un-cluttered. The aim of this circuit is to use PWM to dim a bulb ...
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4answers
162 views

What kind of component would I need to put a break in a RS-485 bus?

I'd like to have some kind of electronically controlled switch (transistor, relay, solid-state relay, etc) that acts as a break in a RS-485 bus. The effect I would like is to optionally split the bus ...
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2answers
66 views

SSR with low-flow switch to control heater

I'm trying to install a low-flow switch (circuit is open below 0.1 gal/min, closed above that) as a safety measure on an immersion heater, but I have some questions about the setup I've come up with ...
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1answer
98 views

Verify relays soldered onto a circuit board

Hello I need to verify a couple of relays for proper functionality. They are soldered onto a PCB as shown in the attached image - labelled RELAY 1 and RELAY 2. Online tutorials take a stand-alone ...
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2answers
83 views

100v audio source volume control / distribution

I have an audio signal from a class-d 100V and 500W. amplifier. I want to distribute this to 16 different sets of speakers and control the volume of each set individually. I am unable to find any ...
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1answer
209 views

Switching frequency of a solid state relay?

I bought a SainSmart 4 channel solid state relay recently. I am planning to use an Arduino to control some Christmas lights I've put up around my home. My question is: How fast can you switch SSR's on ...
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2answers
149 views

Solid state relay (or equivalent/alternative) to drive 6V DC from a 3.3V micro

I have to open/close two wire from a closed device. I cannot open due to it's under warranty, and the only part that I can open and modify is an external button that connects the two wires. Firstly I ...
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3answers
174 views

Should I use a snubber or solid state relays on a 24 vac circuit?

I'm trying to create a smarter controller for my hydroponic systems. I have an arduino controlling a sainsmart mechanical relay. The load on the relays are 24 VAC orbit sprinkler valves. Everything is ...
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0answers
73 views

Flyback (?) diode on the Solid State Relay output

I am looking at the recommended wiring diagram of this SSR and I am wondering about the diode connected in parallel to the load. Flyback diodes for inductive loads make perfect sense to me, but in ...
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1answer
88 views

Problems getting an SSR to turn on

Has anyone had problems getting a solid state relay to work? EDIT: see Spehro Pefhany's answer. Lessons learned: don't accidentally take out current limiting resistor solid state relay rated for ...
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1answer
56 views

Increasing the current to a solid-state relay?

I've got two strings of LED Christmas lights that operate at 120 V / 0.04 A (4.8 W). I'd like to connect them to this 5V solid-state relay: Unfortunately, there's one small problem. According to ...
113
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6answers
10k views

Designing a Santa alarm (honestly)

You read the title and that's what I am trying to do. Synopsis: I have a young son who is determined to catch Santa (to what ends I don't know). He even dreamed up using some kind of pressure plate ...
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1answer
170 views

Solid-state relay realized with bipolar transistor

I'm searching information about SSR realized with bipolar transistor. Basically I need something like tutorial how they are constructed, how they work, what elements they contain etc... I searched in ...
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1answer
82 views

1V output only when load is applied?

I'm working with the Teensy++ 2.0 dev. board. It uses the AT90USB1286 8 bit AVR 16 MHz microcontroller. I'm using the microcontroller to drive a small solid state relay. This was just a basic ...
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2answers
667 views

Do I need zero-crossing detection for controlling a heater?

I need to control a heater element (about 500W) using arduino. For switching part I would go with zero-crossing SSR or zero-crossing optoisolator and triac (the second seems to be cheaper). The ...
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0answers
123 views

LTSpice missing an SSR Component?

I want to simulate some circuits with SSR component but LTSpice does not provide this. From Eagle and KiCad I learned I can create my own component diagram. I'm not sure if I can do this also with a ...
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3answers
110 views

Making my own kotatsu

I want to make my own kotatsu (a small table with an heating element underneath) and I'm considering using a "heat lamp" as the heat source (one of those aimed at reptiles, fits in a normal light bulb ...
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4answers
185 views

Relay alternatives that are silent and support 500mA+

What can I use as a silent "general-purpose" relay alternative? There are various scenarios where I will need a relay-like device that allows me to control one circuit with a separate isolated ...
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1answer
56 views

What's wrong with my static relay connections?

Im trying to use a static relay for the first time. It is an HFS5, supposed to turn on/off at ~5V. Soldering is not clean but I have triple checked with a multimeter that the connections are ok on ...
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1answer
139 views

Normally closed SSR won't work with grounding out a magneto's primary to ground

I've been trying to find a device that will ground out a magneto's coil (primary kill wire) in a normally closed state without using a mechanical relay because I want my circuit to be all solid state. ...
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0answers
49 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
151 views

Dimming SSR Circuit - Verification

I am designing an SSR circuit for the purpose of controlling Christmas lights. Specifically I have the following two goals. Switching & Dimming incandescent strings Switching LED strings - I ...
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3answers
113 views

Can I use this relay for DC

http://www.dx.com/fr/p/ssr-25da-25a-solid-state-relay-white-134494#.VDmPWPl_uap It says AC output but how can this transform DC to AC ? Shouldn't this act like a switch ? If my circuit is DC and I ...
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1answer
208 views

AC AND DC Solid State Relay (SPDT) Circuit?

I have been looking to replace this SPDT switch with a solid state relay. However I learned that the switch could either have a 120VAC or 30VDC or even be used to switch an input on the controller to ...
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1answer
89 views

What kind of protections are needed to control an AC motor (230 V) using a microcontroller?

I need some guidance with surge-protection of the SSR and also how to safely bring the motor to stop (since it's an RL load, the inductive current has to die out). I found a schematic online, but have ...
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3answers
287 views

Standard Relay vs SSR vs TRIAC for Switching CFLs

I'm confused weather I should go for a standard electromechanical relay (EMR) or a sold state relay (SSR) to switch CFLs @ 220V with 100W max load. This is for a commercial product with the following ...
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1answer
297 views

Solid State Relay Capacitance Bad for Audio?

Regarding MOSFET optocoupler relays like the Panasonic AQW212, am I correct in understanding that the capcitance between the terminals and ground when the switch is open ("off") is around 100pF when ...
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3answers
592 views

Solid state circuit to charge caps in parallel then discharge in series?

Do there exist a solid state design circuit to do the following: Charge multiple capacitors in parallel for a certain amount of time from a low voltage DC source, then disconnect them completely from ...
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3answers
431 views

Protecting Solid State Relays from Short Circuits

I have 4 SSRs on my board with a steady state current rating of 2A and a peak current rating of 9A (Relays are CPC1976). This product is meant to be a commercial one and the relays will be powering ...
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2answers
86 views

Using triacs to switch more complex equipment than just motors and lights?

Obviously triacs have been well known to be used in applications which don't really require a perfect sine wave to function. However, what about say a triac to switch on and off more complicated ...
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4answers
465 views

Using an SSR photoelectric sensor with Arduino

I'm wondering if I can use this photoelectric sensor with an Arduino. I don't have much experience with these sensors or with relays, and I'm sometimes confused by output switch ratings, so I can use ...
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2answers
131 views

Voltage drop problem with my solid state relay

My solid state relay seems to be dropping the potential by 35 volts. I read about 80 volts from one end of a modified plug and the other end is plugged into a 120 volt wall socket. I have the hot ...
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1answer
50 views

Ensuring an SSR relay is dead

I recently purchased a used IEC Centra centrifuge with a refrigeration feature. Works great, except the refrigeration condenser never cycles off and as a result the chamber gets down to the minimum ...