I currently have an external power supply with both constant voltage/current sourcing functions.

If it's a bench supply it has an adjustable current *limit*. Constant current power supplies are for special-purposes such as for driving high-power LEDs.

When you disconnect the load from a constant-current power supply, it jumps to maximum-voltage as it tries to push current through an infinite load.

Let's say that there are 5 electronics connected in series that work under the same current value (each 1.6A). Then theoretically a total of 8A current source is required.

**No... Everything in series has the same current flowing through it.**

The voltage divides in series circuits (or we can say the voltage sums-up).

For example, with regular little LEDs rated at about 2V we put a "current limiting" resistor in series. Assuming a 5V source, the resistor has about 3V across it, and the LED has about 2V across it. The same current flows through both.

**There is a common water analogy where voltage is water pressure and electrical current is water flow.** It's not a bad analogy but there are a couple of differences. Nothing bad happens with zero water resistance, and things sometimes burn-out with zero electrical resistance. And if you cut a wire you get infinite resistance and no current flow. If you cut a water pipe you get zero resistance and water flows-out all over the place.

BTW - Resistance is the "resistance to current flow". **[u]Ohm's Law[/u]** describes the relationship between voltage, current, and resistance. Ohm's Law is the 1st thing you learn when you study electronics.

Then, you'd learn Kirchhoff's Laws which describe how current & voltage combine & divide in series and parallel circuits.

Parallel should be pretty easy to understand... If you plug something into wall power here in the U.S. it gets 120VAC. Let's say it takes 10 Amps. If you plug-in something else it gets connected in parallel and it also gets 120VAC. If that 2nd thing takes 5 Amps, you've got 15 Amps flowing. If you plug-in too many things into sockets that share the same circuit breaker, you blow the breaker with too much current.

If it that takes 10A,