| 摘要 |
<p>A power amplifier capable of driving an electro-magnetic vibrator (11) connected across output terminals (12). Normally drive is from a low voltage supply (15) through a bridge arrangement of transistor amplifiers (17, 18, 19 and 20) driven by respective drivers (21, 22) in dependence on the phase of the drive voltage. If a momentary peak drive voltage is recognised, then high voltage amplifier transistors (31, 32, 33, and 34) are driven in series with the low voltage transistors by drivers (35, 36) and a high voltage low power supply (25) is available for the short peaks of power.</p> |
