A lot of you may only know of them in theory and others may have never even heard of them: constant current sources.

Even though current sources are neither difficult to build nor useless! In fact, they are nearly everywhere, but mostly directly inside of the silicon.

Current sources behave in the exact opposite way as voltage regulators (power supplies). Voltage regulators are regulating the current in order to keep the voltage at a stable level. Current sources are regulating the voltage in order to keep the current at a stable flow.

But how do they work, you might ask? Well, in this chapter I wanna explain to you. I will present the most basic current sources and advance from them. Then you will know, how they are looking like in reality or maybe on your next pcb.

I’ll also give some examples for what they might be useful, but you can propably think of more usecases than I will present here 😉