hi folks,
have a simple circuit that is so simple yet I get confused on the "diode" or switch control

I can supply all the details, voltages, motor volts, emf numbers, but what for....

all needed is to simply have one motor run when needed via a switch which wont affect any part of the remaining circuit

also need a flyback diode, but remember, when the switch is flipped it doesn't affect the other circuit either..

please see photo



Moderators note : uploaded picture to forum

 

Flyback diode is correct, but you need to isolate the motor M1, with a second diode in the Negative lead , Cathode to M1, Anode to M2, your switch can then put out a Negative pulse .

 

but but but, that makes M1 turn ?

should the diode be on the positive side ?

 

The flyback diode is well placed. Let me see if I get it.. Do you want to run M2 with the red switch, but not M1? For the sake of understanding, I would suggest to use the proper simbology when drawing schematics, specially for the MOSFET.

 

sorry for the lack of scematics as the Mosfet is an ebay pcb with just the connections, and cant find the schematic

its also smd and bugger me i cant trace the connections as they are also under the chips

so the mosfet just pumps out the input volgtage when the trigger is on

this is the mosfet, see foto

 

https://s19.postimg.cc/cf0ucm1oj/s-l1600.jpg

 

thanks mods for imaging

 

Back to OP, I see M1 and M2 in parallel. Do you want just to run M2 with the red switch? What about M1?

 

Back to OP, I see M1 and M2 in parallel. Do you want just to run M2 with the red switch?
yes

What about M1?

no

 

Let's imagine that we remove M1 from that circuit. How would you turn M1 on? Maybe it would be more clear if you explain your application on two motors in parallel, and their real purpose.

 

M1 can be isolated with diodes or a single or double pole switch