power to microcontroller from transformer help

Hi.

Could I power my micro-controller from this existing transformer and keeping the current circuit intact (see attached pic)? I need about 5V and 1 amp.

I would like to use the white/orange winding. Right now that winding is unregulated and powers relays and a solenoid. The volts jump around a bit depending on what load is switched on.

Could I have a branch coming off this white/orange winding to power the micro-controller? It would have to be regulated down to 5V. Could I keep the existing unregulated branch and this would not affect the microcontroller when the volts jump around?

The second concern would be the back EMF from the solenoid and relays messing with the microcontroller. I do have flyback diodes on them, but could a regulator provide more protection that would be adequate?

Thoughts?

Thanks, pals.

Ideally what I would like is that whole orange/white/orange area regulated along with an extra regulated 5V output.

so :

@ the cathodes of D16 & D17 is the #1 spot DC V that needs regulation

@ the cathode of D7 is the #2 spot DC V that needs regulation

@ point 13 is the #3 spot DC V that needs regulation

and then #4 spot would be a new 5V DC regulated

It is possible that the scheme you suggest will work. You would need to treat it as a new circuit (just using the volts and no existing bits), and add your own diode bridge, capacitor and regulator. (Caveat: assuming the transformer windings have the capacity to carry the extra current.)

Using a 470 to 1000uF capacitor should keep the volts fairly stable from the regulator. I would expect around 8v on the input of the regulator so you could probably get away with a linear regulator, LM7805.

This is just from the diagram, in practice it may be different.

Weedpharma

rrboyd: Ideally what I would like is that whole orange/white/orange area regulated along with an extra regulated 5V output.

so :

@ the cathodes of D16 & D17 is the #1 spot DC V that needs regulation

@ the cathode of D7 is the #2 spot DC V that needs regulation

@ point 13 is the #3 spot DC V that needs regulation

and then #4 spot would be a new 5V DC regulated

Why regulate voltages that just operate solenoids?

Weedpharma

weedpharma: Using a 470 to 1000uF capacitor should keep the volts fairly stable from the regulator. I would expect around 8v on the input of the regulator so you could probably get away with a linear regulator, LM7805.

orange/white/orange output was label 11.5V X 2, diode bridge on both orange will give you 32.5V

white/orange output with diode bridge will give you 16V

I missed the “x2”. :confused:

Weedpharma

weedpharma: Why regulate voltages that just operate solenoids?

Weedpharma

My concern was : Say I rectify an orange/white output and get the 16V. I then regulate it down to 5V for microcontroller and lcd power. This new power bridge is still coming off the same winding as the solenoids and relays. When the loads change on the microcontroller won't this make the volts jump around on the solenoid and relay branch area? But maybe the load changes aren't large enough to make a difference?

Thanks for the help.