| 摘要 |
<p>A portable A.C. power supply comprises D.C. to A.C. inverter means, including a chopper circuit (18) and transformer (22), connected to D.C. storage cells (at V). The supply includes control means responsive to the current being drawn by the load (16) (such as a power tool) which de-activates the supply if the alternating current drawn by the load (16) falls below a predetermined level, e.g. if the tool is switched off, and re-activates the supply automatically when the tool is switched on again. The supply also allows the storage cells to be re-charged via the windings of the output transformer (22).</p> |
