On Wed, 19 Jan 2000 15:01:36 -0800 Lee Jones writes: >That's 0.9 to 1.5 watts. At 3 volts, current required (0.3 to 0.5 >amps) exceeds the rated delivery of even an alkaline D cell. At >the higher voltages, a cell might be able to handle the current flow >but battery life could be unacceptable. I don't know what battery specs you are looking at, but I just checked the duracell web site, and the performance curves for AA cells are plotted out to 1 watt EACH. The discharge curve for D cells is plotted for loads up to 2 amps, but of course no curves are available in watts. 2 AA cells can put out 1W for 2 hours, terminating at 1.0V. 2 D cells could do it for 18 hours or so. This load will be intermittant and only a few seconds at a time, so that kind of lifetime is acceptable. >Are you sure you need that much current at 300 VDC? No. It might be higher. Worst case it could be 7 mA, but I'm hoping to keep it to 3 or less. Unless the customer decides to expand the thing again... Really, what I want is 100-110VAC sine wave at 700-900 Hz, 10 mArms to drive an EL panel. I've been thinking to build a DC-DC to get 300 VDC, then use a class D (switching) amp to generate the sine wave. I'm hoping that since the EL is mostly capacitive, and the switching amp is way more efficient than a linear, the load on the 300V will be no more than 3mA. But since I've yet to build any of this, I have no idea what the real efficiencies will be. And before you ask, my customer insists it must be sine wave. I know it would be much easier to go with some kind of filtered square wave, but he won't hear of it. Any ideas welcome. Don