Snap - action Miniature switch how to build and operate

Snap - action Miniature switch how to build and operate

A long flat spring is hinged at one end of the switch (the left, in the photograph) and has electrical contacts on the other. A small curved 1M0680R spring, preloaded (i.e. compressed during assembly) so it attempts to extend itself (at the top, just right of center in the photo), is connected between the flat spring near the contacts. A fulcrum is near the midpoint of the flat spring. An actuator nub RJK5020 presses on the flat spring near its hinge point.Because the flat spring is anchored and strong in tension the curved spring cannot move it to the right. The curved spring presses, or pulls, the flat 2n4427 spring upward, that is away, from the anchor point. Owing to the geometry, the upward force is proportional to the displacement which decreases as the flat spring moves downward. (Actually, the force is proportional to the sine of the angle, which is approximately proportional to the angle for 2N3055 small angles.)As the actuator depresses it flexes the flat spring while the curved spring keeps the electrical contacts touching. When the flat spring is flexed enough it will provide sufficient force to compress the BA5104 curved spring and the contacts will begin to move.