Hello everyone!
I'm currently trying to toggle a valve on and off, have a preliminary circuit but thought I'd bounce it off of you guys and see if you have a better approach.
I have a 6.5W valve that operates at 24VDC (+/- 10%), so I'm expecting it to pull about 270 mA of current.
I basically have a circuit that is controlled by a 5V microcontroller signal that I'm switching on and off using a transistor as a switch and a BUF634U (which is rated at 250 mA of current) to generate the necessary current. I'm attaching the circuit I have.
I have a few concerns:
1) THe BUF634U is rated at 250 mA of current. If my calculations are correct, I'll likely need about 270 mA of current. I'm guessing I probably need to switch over to an OPA547, right?
2) I'm using a BJT to be used as a switch. Should I consider using a FET instead? What are the advantages/disadvantages of each? Is one more preferable if I'm looking to switch these on and off quickly?
3) Do I need/should I have a flyback diode on the resistor?
Let me know if anyone has a better approach to doing this or has any suggestions. In my head, this is the way to go but I'm nowhere near as experienced as I'd like to be and I figure there are lots of more experienced EE's in here. Thanks for your time!