The working principle of the metal shrapnel: the metal shrapnel on the membrane button is located on the conductive part of the PCB (mostly above the gold fingers on the circuit board). When pressed, the center point of the shrapnel is concave and contacts the circuit on the PCB , so as to form a loop, the current passes through, and the whole product can work normally.
Generally, conventional metal shrapnel are divided into: round metal shrapnel, cross-shaped metal shrapnel, triangular metal shrapnel, and oval metal shrapnel according to their different shapes. Diameter from 3mm to 20mm, strength from 100g to 600gf. Of course, if you have special requirements to make according to your drawings, there is no problem.
And according to the customer's requirements for resistors, our metal shrapnel also has nickel-plated, silver-plated, gold-plated and other surface treatments.