Hello!
What is a good relay to pair up to the Arduino which may accept the Arduino's voltage/amperage on a pin, and switch a 0 - 24VDC load of about 2 amps? I tried looking through Mouser, but I struggle with understanding the filters there.
I was considering a solid state relay for it's reliability and low power requirements to the Arduino.
I'm open to suggestions, but I was looking for through-hole components because I'll be placing this on a PCB at some point.
A single MOSFET would accomplish that unless they need to be isolated. I have used several of these, no problems: https://www.aliexpress.us/item/2255800880018979.html?spm=a2g0o.order_list.order_list_main.117.5d3218023PxCiw&gatewayAdapt=glo2usa&_randl_shipto=US They have opto couplers so the grounds do not need to be connected.
For that, just a single relay won't be enough. You will need to add a fly-back diode, and something to switch the relay, usually a transistor. The current required to switch the relay exceeds what any Arduino can provide on a single GPIO. There are modules available that include these parts (and some more) .
Design your circuit on paper before buying stuff. Paper is cheap, as are pixels.
You need to do a bit more research on your requirements. A relay is just a coil and a switch linked together. The coil is on the logic side (where your arduino is) and the switch is on the load side. You need to think about the coil requirements in terms of voltage and current and how you can convert your logic signal from the arduino to match. The important thing is that the arduino supplies logic (low voltage and current) not power. You need to understand that coils, when switched off, collapse the EM field and create large spikes of voltage which can damage sensitive components.
So
Mouser has multiple SSR that match. For example 558-CN024D05. 24VDC 3,5A
Hi,
I don't know if I understood your need correctly.
Do you want to: "switch a 0 - 24VDC load of about 2 amps" ?
If it's VDC, you can't use SSR, because they don't control VDC, only VAC.
The solution is to use a MOSFET, (most recommended), or a relay.
Unless they do
a7
There are multiple SSR that control DC. There is a MOSFET in it and mostly a led input.
I have switched DC with relays for many years, you just have to abide by there specifications. You need to pick the correct device to succeed. Mechanical relays do not normally care if it is AC or DC. When switching DC with electronics it is dependent on the design and selection of the components used to accomplish the solution.
This will switch DC. Isolated MOSFET MOS Tube FET Module Replacement Relay 100V 9.4A 30V 161A 40V 50A Board Module, See my link in post #2 for more details. I have used several for loads upto 4 amps.
There are several variations of these modules. The pin inputs are for the control signal to the opto isolator. maybe 10mA or so. 2A is well within the ratings of these devices as is 24V.
Do you really believe that the used boards and connectors are good for 40A? The pinheaders are rated at 3A. The screw connectors are rated at 16A. 50A need at least 10mm² 8AWG wire. How do you place that in a 3 or 4mm screw hole?
Thanks for the recommendation. I went with the Crydom CN024D05 relay. I had a senior moment and couldn't get the relay to function correctly at first. My load was always powered on! This was regardless of the A1 A2 pins, as nothing was connected to them. I looked up freewheel diodes, RC snubber circuits, and made myself even more confused. One search term revealed a guy who suggested that he wired the load backwards! So, for the next poor soul that needs a "How'd the other guys do it?" here's my working diagram:
This is a really good suggestion that I will work on. I went with another's suggestion for a relay as I had a little bit more experience with those and needed to get something done quicky. I considered a MOSFET, but had concerns of the heat (as well buggering it up with my inexperience using them). I'm going to order these since they are FAR more affordable than a SSR and see if I can make this work. Thank you for your suggestion!
You don't need a flywheel diode or a snubber network, the SSR is just an opto-solated mosfet
I tend to use this method, even when building with discrete components. Nothing like good isolation to protect the MPU
Info: the flywheel diode and snubber networks are used on inductive loads
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