I've included a diagram to help convey what I have going on here. I'm mostly self taught so I can definitely some use feedback if anyone has any suggestions or if you see something I am doing wrong (ie: Am I using the right resistor for the base of the transistor? Is the transistor going to reach saturation?)
I have 2 channels of 12v solenoid valves which are being controlled via a micro-controller. I am using a TIP120 transistor for each channel. I am turning the valves on and off very quickly. Valve is open for ~50ms, then closed for 150ms, for a total of 5 cycles per second.
I need some flyback protection but I honestly have no idea what the best approach is and how much protection I need. I know a flyback diode will slow the rate at which I am currently controlling the valves and that may be a compromise I have to make.
Should I use a single diode for each channel, which is placed right after the transistor? This would make for a total of 2 diodes.
Or do I need a diode for each and every inductive load, making for a total of 19 diodes as they are attached directly at the valves?
How do I then go about calculating which diode will meet my needs without severely compromising the speed of which I can control the valves?
I have 2 channels of 12v solenoid valves which are being controlled via a micro-controller. I am using a TIP120 transistor for each channel. I am turning the valves on and off very quickly. Valve is open for ~50ms, then closed for 150ms, for a total of 5 cycles per second.
I need some flyback protection but I honestly have no idea what the best approach is and how much protection I need. I know a flyback diode will slow the rate at which I am currently controlling the valves and that may be a compromise I have to make.
Should I use a single diode for each channel, which is placed right after the transistor? This would make for a total of 2 diodes.
Or do I need a diode for each and every inductive load, making for a total of 19 diodes as they are attached directly at the valves?
How do I then go about calculating which diode will meet my needs without severely compromising the speed of which I can control the valves?