DEVICE WHICH VERIFIES BANKNOTE VALIDITY Russian patent published in 1997 - IPC

FIELD: testing bank notes which picture is generated by paint which provides possibility of composition of infrared marks. SUBSTANCE: device has photodetector of infrared marks, which output is connected through high-pass filter to first input of comparator. In addition device has reference voltage source which terminal is connected to second input of comparator, and final circuit. In addition accumulation capacitor and discharge resistor are connected in parallel to input of final circuit. Output of comparator is connected to input of final circuit through serial circuit of separating capacitor and first diode. Second diode is connected in parallel to serial circuit of first diode and accumulating capacitor. Polarity of second diode is in aiding to that of first diode. EFFECT: improved design of electric circuit, increased validity of checking due to elimination of false alarm. 13 dwg