AC-line on off with transistor. how exactly?

Hi All, I have a relatively low voltage (10V , 50mA-ish) AC line that I want to turn on and off with Arduino, I am not exactly sure what is the most agile and least resource consuming option.
After my research it seems that what I need is two MOSFETs connected back to back in this configuration like the one in attach (I found on internet) so when I send current to the gates from arduino pin, transistors will open and current can flow in both directions and if I do not send current to the gates from arduino they will be closed and that AC line will not pass anything.
Couple questions:

  1. Are those N-channel?
  2. Do they have common drain or source or that does not matter?
  3. Just to confirm, I technically can just buy a chip that has two FETs in it.
  4. Are there other ways to block/enable and AC line with arduino? I just came across insulated-gate bipolar transistor, that seems to do similar stuff but I am not yet sure as I just discovered about it this morning and doing some reading, it seems that it is designed to mostly control high voltage lines and my experiment is low voltage.

Thanks for any advice.

acmosfet.png

One option is to rectify the AC current (e.g. with a diode bridge module) before you switch it. You lose 1.2-1.4V in the diodes, but it is a simple circuit.

For DC-AC circuit isolation, use a relay or optocoupler for the switch.
bridge.gif

Understand that in the schematic and explanation in #1 above, while the MOSFET is dealing with rectified AC (so it is only seeing DC), the load "RLoad" is basically still seeing AC (it will have some funny transitions in the sine wave around zero due to the rectifiers, but otherwise, it is still AC.)

Considering that with 4 diodes and mosfet it is 5 elements circuit and with illustration from 1st post it is only two mosfets, wouldn't that be easier to do the one from 1st post? Or there some other disadvantages?

transistors will open and current can flow in both directions

We never talk of transistors 'opening' or 'closing', that's very ambiguous language, they switch on or off.

An open water tap is conducting water. An open circuit conducts no current
A closed tap stops the flow, a closed circuit is flowing. In languages other than English
open and closed mean something, but not the same in every language!

On and off are clear and don't lead to confusion.

Considering that with 4 diodes and mosfet it is 5 elements circuit

As I stated, you can use a diode bridge module, which is one component.

The circuit you posted is incomplete, so it is unclear exactly how it was intended to be used.

If you don't want to use a relay, a solid state relay could work. [u]This one[/u] looks like it would work. (This particular one needs an external current limiting resistor for the internal LED.)

Just make sure to choose one rated for AC, low voltage, and low current. Some AC solid state relays only work properly at power line voltages.

“10v, 50ma-ish”.
How “-ish”?
For what?

VO2223

I have two devices and one speaker, so I want to be able to switch between devices digitally.

If the speaker is in the position of RLoad, then while high intensity signals will be mostly OK, lower volume stuff is going to get really distorted by the diodes.

None of these ideas are workable with speaker audio, unless you are happy with scratchy intercom quality sound.

jremington:
None of these ideas are workable with speaker audio, unless you are happy with scratchy intercom quality sound.

The speaker circuit is my test circuit, I do not really care about quality, I am learning and more after figuring out how things work.

Is there any problem in using a Relay? Which can on/off AC or DC devices.

Hi,

sarouje:
Is there any problem in using a Relay? Which can on/off AC or DC devices.

Exactly, its isolated and you are sure of a good switching action.

alexmg2:
The speaker circuit is my test circuit, I do not really care about quality, I am learning and more after figuring out how things work.

So start with a relay and then try other ways.

Tom.... :slight_smile:

Yet again, the "XY problem"!

Paul__B:
Yet again, the "XY problem"!

That's how you learn new stuff in unique way and be different.

alexmg2:
That's how you learn new stuff in unique way and be different.

Or chase wild geese.