tilt

tilt elektor december 1980 — 12-33 P. Groger reacts to any movement of the can by swinging and thereby effectively closing a switch. As can be seen from the block diagram, the remainder of the circuit is very simple. The pendulum triggers a monostable multivibrator which in turn activates an astable multivibrator in the form of an audio tone generator. As soon as the pendulum touches the contact loop (see circuit diagram), the electrolytic capacitor at the input of the circuit will charge up rapidly via R2. Transistor T1 will conduct and activate the Schmitt trigger formed by T2 and T3, which turns on the oscillator (T5 and T6) via transistor T4. If the can is at rest and the pendulum no longer touches the contact loop, the electrolytic capacitor, C1, will discharge through the base-emitter junc- tion of Ti. Only when the capacitor is discharged to below about 0.7 V will T1 turn off thereby inhibiting the oscillator via the Schmitt trigger and T4. This means that the oscillator ...