U-type flat spring, see fig 2, precursor to transistor https://www.calling315.com/relay-logic https://www.calling315.com/relay-logic The user facing switches

U-type flat spring, see fig 2, precursor to transistor https://www.calling315.com/relay-logic https://www.calling315.com/relay-logic The user facing switches are 'A' & 'B'