I think your description is fine at that level of detail. As it happens, I do pretty much understand it. But it would not stop me appreciating the story if I scarcely understood the technical aspects at all, so long as I understand what his success or failure in building a radio means for the character.
In this case it is clear that the character is marooned. He is cannibalizing the remains of the ship to send a message so that he can be rescued. We understand that he is in peril but rescue is possible. We understand that he has some technical knowledge and is a resourceful person who does not give in to despair, making us inclined to admire him. These are the things that 100% of the readers must understand to make them care what happens next. So long as you achieve that, it doesn't matter that a much smaller percentage of your readers will be able to remember from college what a capacitor is, and a smaller percentage still would be able to check whether your description is correct.
Let me give an example from a field of knowledge I scarcely understand at all. I have read all of C.S. Forester's stories featuring Horatio Hornblower, an officer in the British navy during the Napoleonic Wars, several times over. I still have only a hazy idea what a mizzen mast is or the difference between a sloop and a frigate. But I have confidence that Forester did know. It does matter that the author gets it right: an author writing about a subject that they have researched well writes with confidence, and that confidence is picked up by the reader and makes them believe in the story. But it matters much less whether the author has fully transferred their technical knowledge to to the reader. The important thing is that the practical and emotional consequences of technical facts are conveyed. I could be gripped by every stage of a lengthy description of the manoeuvres of a sailing ship in a storm or in battle because the survival of characters I cared about depended on their doing these difficult manoeuvres successfully. It doesn't have to be life or death; I have often been fascinated by stories about the process of scientific discovery, but to fully awaken my sense of wonder I needed a human being in the story to be feeling that wonder too.
You could, if you wanted, write a lot more about your character building that radio. How exactly did he "gather wire" and find those components? Don't make it easy for him! Maybe he suffered agonizing frustration when he realized that the tools that would have made the job easy were out of his reach under tons of wreckage. Perhaps he had to improvise a lever from scrap metal to open a panel, cutting his hands, only to find that the component he had thought he could use was smashed and he would have to do it all again. Maybe he had to crawl past the dead bodies of his crewmates to get into the ship at all. If you want to add more technical details (What diameter wire? What was that capacitor originally being used for?), feel free, that's what readers come to science fiction for, but make sure that you intersperse every technical fact with an emotional fact ("If this doesn't work I'm done for") about characters the reader cares about.
Aim for something like this scene from the 1965 film The Flight of the Phoenix. Few people know exactly how a Coffman engine starter cartridge works, they just know that they are crucial and the castaways have a limited supply of them. Everybody understands what a tense moment it is when
Dorfmann panics when four cartridges fail to start the engine and
Towns wants to use one of the remaining three cartridges just to clear
the engine's cylinders. Dorfmann objects, but Towns ignores him and
fires one cartridge with the ignition off. The next cartridge