Converting a DPDT relay circuit to MOSFETs or Transistors?

Hi Folks,

I have a scenario that I am trying to figure out how to resolve. I should start by saying I am still quite a newb at electronic engineering, as I am more a software engineer than a hardware one, but I am learning the hobby and having fun with it.

Here goes!

I have a DPDT relay, a Panasonic TQ2-5V. The relay uses 5V at the coils and is switching two paths of electrical signals. When the relay is not active, it is allowing a 5V PWM signal to come in one side and out the other. When the relay is active, it is allowing a 5V pure signal to come in one side and out the other. What is making or breaking the relay’s coils is a simple SPST switch that is either giving the relay ground or is leaving the ground leg as floating.

What I am trying to do is do that same circuit, but without the relay. I am a little familiar with Transistors and MOSFETs, but when I have seen them used, typically, you send a positive signal to make them switch on an off, which I am not doing (I am sending either ground or float). And I remember pretty well that if I leave Gates on a MOSFET in a floating state, ringing occurs on that pin and the MOSFET locks up. But there probably is another way that I don’t know about. As I said, I am a newb at this.

Is this possible to do without the relay, but with Transistors or MOSFETs?

Thanks for any replies,
Erik

Below is the attached schematic of the Relay circuit I am trying to make.

Why are you using a relay at all - why not just a SPDT switch?

Do you need electrical isolation between SW1 and the switched PWM/5V signal?

The circuit is simply a changeover from 5v to PWM. As has been said, a SPDT is all that is needed.

If the signal is low level IE, just for logic, it can be done via software. Simply change from logic high to PWM.

You could use P MOSFETs to select one or the other.

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