Gas alarm system having timer with delayed response - which is connected to second input of logic circuit including AND=gate or NAND=gate

摘要

The system has gas sensors, a measurement amplifier, a threshold switch and a switching amplifier with switching means for the output. A logic circuit (4) with two inputs and one output is inserted between the measurement amplifier (2) and threshold switch (3). Its first input (E1) is connected to the amplifier (2) output, and a timer (5) with response delay is connected to the second input (E2). The logical connection unit (4) has two inputs (2) and one output (1) and may be an AND gate or an NAND gate. The timing unit (5) incorporates a resistor and a capacitor (R1, C1).