# Possible to distribute current source with switches?

Hello everyone,

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

I’m wondering if this idea is feasible and if so how to design the system.

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. I also want to control each electronics separately with 5 switches. If I only want 2 out of 5 to work, then I will switch off the other 3 while keeping the current source constant at 8A. The 2 electronics will still receive 1.5A, respectively.

It will almost work/look like a power strip with each socket switched on and off by each switch.

Thanks!

Are You shure You are using the proper expressions? What is serially connected and what is parallell?
What is volt and what is ampere, current?
Your qeuestion makes no sence to me. What kind of loads do You intend to connect to the Power source?
What is the final project?

Thanks for the quick reply, and I’m sorry for the confusion I made in the writing. I’m very new to electronics.

Loads can be anything like LED. Then the current should be in the range of tens of mA. Now that I think about it, like you pointed out, the loads should not be connected serially. Then I cannot control each separately. Right?

All I want is to control each load separately with a corresponding switch

You could connect LEDs in serial and run a constant current through the chain of LEDs. Controlling them individually can be done by switches just short circuiting them individually. Then You must add all the voltage drops and make shure that Your constant current supply has voltage enough. Don't use too many loads that will need hundreds of volts.

The most usual way would be connecting them in parallell. Then the sum of the currents must be available from the power supply. Each load is connected to ground by its switch.

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,