Home depot has a universal thermocouple that I can get. According to the website it will work on appliances. My question is should I get the universal unit or order the replacement from an appliance parts store. Am I over thinking this one ?

Unless it is a commercial type stove/oven
I have not seen a regular thermocouple on a domestic oven in 30 years
Maybe a flame switch or electric glow ignition

Now I'm confused. Maybe I'm using the wrong terminology. I'll check the parts diagram I found and try to figure this out.

Brand and year made

oven temp sensor [ohms change as temps increase or decrease] or thermostat with temp probe. [old style, uses liquid that expands or contracts with heat that operates the attached thermostat]

Amazon universal for the win.

My local appliance store wanted $80 for what Amazon had for $15

That is for a thermocouple that senses if the pilot light is lit in order to allow the gas to switch on.

It's a whirlpool. I'm going to try to clean the igniter. Apparently the igniter sends a signal to the gas valve. So there is no thermocouple involved.

Is it the type that sparks twice and if it doesn't ignite it shuts down for 5 minutes or so and tries again?

If so, remove it, carefully clean it with emory paper and adjust it so it's closer to the burner. They tend to warp away from the burner as time passes and it's a very unforgiving system when it comes to ignition. Make sure the point on the protective surround is lined up with the electrode and the edges of the surround it is on are even with the other sides of the surround. Easy to remove and only one lead to remove, remove the entire burner and then remove the electrode from that. Use a drop of penetrating oil on the screws before you remove it as they threads will strip easily and the temp swings will lock it in place.

Ok, I opened up the bottom of the oven. When I turn the oven on the igniter arcs and lights the burner tube. When the flame travels from the ignitor side around to the opposite end of the burner
the gas shuts off and just goes out.

There's no problem with lighting the oven, just keeping it running

It's not reading back to the board telling it that the burner actually lit. The flame is the electrode voltage path to ground, [burner] clean it. It has to get a read within a couple seconds, if it doesn't, the board will cut power to the valve.

I'll try that, thanks.

Flames conduct electricity very nicely.
That is how all those high voltage starters know when to stop sparking.
There is usually a larger burner hole adjacent to the igniter contacts.

When the burner ignites the flame leaks enough voltage to shut off the igniter circuit.

It is a great improvement over the capillary tube systems, and the original low voltage igniter sense circuits.