Many people ask me this.
But that’s like if you want to learn the piano and ask: “How to combine notes to play a specific song?”
What you need to do to learn to play the piano is to practice playing the piano.
No matter how much music theory you read, you need to play the piano to learn how to combine notes to play specific songs.
After a while you’ll learn which note sounds good together. And you get a good ear for which notes are in a song, so you can play it by ear.
It’s the same with electronics.
Practice building electronics, and you will learn which combinations of components that give you specific functions.
Start with the basics.
Learn what each component does on its own.
Then continue to build simple circuits that combine the basic components.
When you got the basics down, try something harder. Find schematics online. If you need a timer for a project, look for a timer circuit diagram. If you need to sense light, look for light-sensing circuits.
I’ve also written an eBook that covers the basics and that takes you through this first phase, to get the basics down. And you’ll get to build really cool things too. Find it here:
Also, if you ask more specific questions, you will get more specific answers.
Instead of asking “How to combine components to get a specific function?”
Ask for example “Which components should I learn about first?”
“What does a timer circuit look like?”
Keep on Soldering!