摘要 |
<p>A vehicle horn with an electronic solid state energizing circuit (100) is described. The horn has an electromagnet for driving diaphragm assembly which has a resonant frequency of mechanical vibration. The energizing circuit generates a DC pulse train for energizing the coil (70) of the electromagnet to drive the diaphragm. The circuit has an adjustment (86) for setting the pulse repetition rate of the pulse train substantially equal to the resonant frequency. It also has an adjustment (92) for independently setting the duty cycle of the pulse train. The circuit further includes a compensator (82) for varying the duty cycle inversely with changes in the supply voltage. An electronic power switch (64) is connected in series with the vehicle battery and the horn coil through an unswitched power circuit. A horn switch (72) is connected in an on/off circuit which connects the battery to a control circuit for generating the pulse train and applies it to the electronic power switch.</p> |