Transmission of voltage signals through serially connected relay contacts

When more than one switching contact in series transmits electric signals, the high-resistance tail of the contact resistance distribution function has an influence on the voltage fall statistics of the contact series. Due to this effect, the reduction of voltage-fall on the receiver can result in reduced reliability of its operation. When the behavior of contact series is concerned, some characteristics of contact contamination can be distinguished from statistical treatment of transmitted voltage, measured on the load resistor. Voltage fall statistics of a multicontact system, when assuming Weibull distribution function of contact resistance for individual contact, were derived from basic probability analysis for nominally clean contacts. It can be helpful in the research of contaminated contacts with non-Weibull statistics in order to recognize some contact surface phenomena