Hi all, I want to use a spring and a solenoid in opposition to create a locking mechanism. Nice and simple - the solenoid has to pull a peg vertically out of a hole when activated, and the spring will supply the returning force. I know that my solenoids (at least the ones I have been looking at on the RS website) have a very steep fall off in force applied as the Stroke length increases. For example, the solenoid might apply a 50N force over 1mm, but by 10mm, the force could have dropped by 75%. My question is, do springs behave in a similar way? If I have a 20N spring in conjunction with this solenoid, will the spring apply more or less force as it is compressed or is it constant? Make sence? I'm sure I have the answer in a physics revision guide but thatâ€™s AAAALL the way at home! Ta!