相關(guān)元件pdf下載：bc547 bc557 
any number of nmally open switches may be used. fit the mercury switches so that they close when the steering is moved when the bike is lifted off its side-st pushed fward off its centre-st. use micro-switches to protect removable panels the lids of panniers etc. while at least one switch remains closed, the siren will sound. about two minutes after the switches have been opened again, the alarm will reset. how long it takes to switch off depends on the acteristics of the actual components used. but, up to a point, you can adjust the time to suit your requirements by changing the value of c1.the circuit board switches must be protected from the elements. dampness condensation will cause malfunction. without its terminal blocks, the board is small. ideally, you should try to find a siren with enough spare space inside to accommodate it. fit a 1-amp in-line fuse close to the power source. this protects the wiring. instead of using a key-switch you can use a hidden switch; you could use the nmally closed contacts of a small relay. wire the relay coil so that it is energized while the ignition is on. then every time you turn the ignition off, the alarm will set itself.when it's not sounding, the circuit uses virtually no current. this should make it useful in other circumstances. f example, powered by dry batteries with the relay siren voltages to suit, it could be fitted inside a computer anything else that's in danger of being picked up carried away. the low stby current automatic reset means that f this st of application an external on/off switch may not be necessary.
