Electrically-conducting strip detection system for document or banknote has transmitter and receiver electrodes on either side of banknote and has function generator and resistance measuring circuit

摘要

A function generator circuit (3) is connected to a transmitter electrode (1). The banknote (10) being tested passes through the gap between the transmitter electrode and a receiver electrode (2). The resistance across the two electrodes varies with the frequency generated by the function generator and whether paper or a metal security strip (11) is between the two electrodes. The receiver electrode is connected to a measuring circuit (4) connected to an evaluation circuit (5).