New answers tagged relay
3
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How can I calculate a relay's series resistor?
There definitely is a reason to limit the holding current of the relay, especially if you care about the power consumption. For that case one may use parallel RC circuit in series with the coil. The ...
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8
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Is it possible to drive a relay with 220VAC coil without a triac?
The Opto Triac that you linked contains a 400 V triac. This is marginal for a 220 VAC line (220 * 1.707 = 375 V). You should use an Opto Triac from the MOC3163 Series, they are rated for 600 V.
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9
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Is it possible to drive a relay with 220VAC coil without a triac?
It will probably work. You may need an RC snubber to get it to commutate reliably with an inductive load like that.
Keep in mind that 400V is a bit marginal with 220VAC mains anyway, so I would ...
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4
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Declaration of Relays
Contact: 250 VAC/28 VDC 10 A RES; 250 VAC 7 A GEN
The contacts are rated at 250 V AC carrying or breaking 10 A when powering a resistive load.
The contacts are also rated at 28 V DC carrying or ...
- 162k
2
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How can I calculate a relay's series resistor?
Very good question... It takes me way back to my 70s school days when I was making all sorts of devices with relays. Then I reasoned like the OP does now:
The relay coil was wound with copper wire, ...
- 14.9k
0
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How to wire two DPDT relays in parallel?
The contacts will not open and close at exactly the same time. You may do some measurements with a digital scope to see if the time differences are small enough for you. But you need a lot of ...
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How to wire two DPDT relays in parallel?
Just to add my 2 cents worth ...
Whether you have 2 relays or a 4PDT, there will be mechanical delays and bouncing during contact.
If your timing requirements, for all connections to be at a stable ...
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2
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How to wire two DPDT relays in parallel?
When paralleling the coils that would be the way to wire it. You would need to make sure whatever is driving the coils can handle the combined current.
Since there will be some slight differences in ...
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6
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How can I calculate a relay's series resistor?
If you have a 5V relay, you give it 5V without series resistors.
I guess what you have been told applies to a case where you have e.g. 12V supply and relay with 5V coil, then you need to have ...
- 137k
3
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How can I calculate a relay's series resistor?
The value of 140 mW is not its rated power; it is just its nominal power dissipated at the nominal voltage. It is completely fine to operate the coil directly from 5 V DC, as long as 5 V DC is within ...
13
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How can I calculate a relay's series resistor?
I have been told that always that I add a relay to my design I have to include a series resistor (series with the coil) to limit current in it.
This is wrong advice.
The relay's datasheet will tell ...
- 171k
1
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Residual current relay continuity
The RCD should not be damaged by triggering at its design leakage trip point, as long as the interrupted current is within the design range. Most devices will have durability limits of 1000s of trips.
...
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5V Relay, triggered with power on/off
The first board at least (I didn't look at the second) is "active low," so if you want the relay to be actuated anytime it's powered, just tie the logic input to USB ground. (If you tie it ...
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1950s Era primary and secondary low voltage intercom system
With a low voltage system you should have a box full of relays. The relay contacts control your 120 V lights. The relay coils are energized by a low voltage. So your light switches will switch the low ...
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Can I use just two relays to switch between two 3-phase brushless motors sharing the same driver?
Yes, that should work.
Here's the schematic.
However the conventional method is to use a single 3PDT latch relay as shown below.
The latch relay ensures that the selection is maintained even after ...
- 17.5k
0
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How much clearance do I need for a terminal block that will run at 240VAC, 10A max?
You have the IPC rules, however these assume your board is clean.
It may not remain clean, or not be as clean after soldering.
Based on experience we use the following drc rules:
Masked traces 2.5mm
...
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2
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How much clearance do I need for a terminal block that will run at 240VAC, 10A max?
IPC-2221 table 6.1 lists a few numbers that will be of interest. In particular is the column B2 for soldered pads to other non-protected copper and, column B4 for tracks under solder resist (permanent ...
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1
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Can anyone help me write a program in Python to output 5V from a USB port to control a relay?
Perhaps the simplest way to get single bit I/O from a PC is to use a USB serial lead (they are all over AlliBayZon for a few $£€), and the pyserial library (not serial, that's something else) with ...
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Simplify a relay based latching circuit
This arrangement should work true to the original concept. It is not an extreame improvement but it does eliminate the DPDT relay, and the other relays can be simplified.
Use two SPST relays, one SPDT ...
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Simplify a relay based latching circuit
I have a solution that uses a single chip to perform the logic and drive the power relay. It uses an array of medium-power (for an IC) Darlington transistors as open-collector, high-current inverters....
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Relay control using ESP32 via a transistor
When you bias the transistor's base with a Current, you basically tell the transistor how much current it allows to pass from its collector to its emmitter. You need to know the \$ h_{FE} \$ or \$ β \$...
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Simplify a relay based latching circuit
Here's the simplified schematic.
It is presumed that the power relay 'K1' does not have auxiliary contacts.
Hence a standard relay 'K0' has been used for the control function.
Also, a standard single-...
- 17.5k
0
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Thermador oven circuit board troubleshooting - where to go from here?
Tested the board during cycle through the wiring harness and along individual traces and found the relay (Bake - K1) to be at fault.
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0
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Relay optocoupler driver
5 - 2,2 - 1,2 = 1,6 :-)
1,6/0.02 = 80 Ohm if 20 ma needed.
With 1k Ohm, it gives 1,6 ma current.
Out of figure, it is more or less at maximum ctr.
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1
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Accepted
Would this Omron G5V-1 DC3 be suitable, even at my battery's 4v2 fully charged voltage?
The contact resistance of S1 is 100 milliohms, not 100 ohms.
I don't see anything in the relay datasheet about operation at 200% of the coil voltage as pulsed or some other form of non-continuous. ...
- 18k
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Does a diode flyback protection decrease the life of the relay?
Let me collate everything I have gathered so far:
To answer the main question of does adding a flyback diode to a relay coil reduce its longevity.
YES IT DOES
This is coming from articles from ...
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0
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Thermador oven circuit board troubleshooting - where to go from here?
I am not sure if you ever figuered this out, but I am having a similar issue. I assume the picture of the board you showed is the board you took out of your oven. There is a burned area on your board.
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How to temporarily disconnect a relay coil to guarantee that it unlatches
If the battery protection circuit truly protects against over-discharge then I would expect that the battery should connect to B+ and B- and the load (motor) and the charger both should connect to P+ ...
2
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How to temporarily disconnect a relay coil to guarantee that it unlatches
You could connect the relay coil positives before the Schottky diode. This would switch the relays when +Ve is applied, and when it’s not the diode would block the battery voltage from energizing them....
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GoKart brake/flashers with 5-pin relay help
That looks like it will work, but I would change one thing. Relay pin 30 is connected directly to battery positive, so when the ignition is off there is still power going to the yellow wire. Since the ...
- 19.5k
6
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Does a diode flyback protection decrease the life of the relay?
The TE connectivity paper explains the reasoning very well.
I will quote the core part here, but reading the paper is recommended.
TE Connectivity are leaders in their field.
TL/DR:
A diode across a ...
- 149k
1
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Controlling 3V3 relay from 2V8 (VL53L1X) GPIO output with PNP transistor
You can "offset" the 2.8V digital control signal upwards by about half a volt, with a single diode, D1 here:
simulate this circuit – Schematic created using CircuitLab
D1 develops ...
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2
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Does a diode flyback protection decrease the life of the relay?
Suggestion:
simulate this circuit – Schematic created using CircuitLab
There should be a diode across the MOSFET (D1). There is already a diode included with the MOSFET but it's good to double ...
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9
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Does a diode flyback protection decrease the life of the relay?
Like everywhere else, this is a compromise between two things, the transistor surviving the flyback, and the relay armature getting released quickly to break the contacts.
The diode is just the most ...
- 137k
0
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Current rating of relay with daisy chained parallel power supply
So can I still use a relay with this rating?
Yes, you can, since each relay switches on only one appliance.
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