I don't know what the Apple ][ or // used in the way of current, but Commodore PETs of that date used 2 to 4 amps, I think. (Early PETs, iirc, had 4 1A regulator chips on different bits of 5V rail). You want something to draw around 1/2 to 1 amp. 6V torch (flashlight) bulb - one of the nice krypton ones that runs of a big rectangular battery would be ideal. 12V 10W car lamp bulb would do, though it won't glow more than dull orange when working. 10 ohm resistor would work, but it probably needs to be a really big fat one - in a rectangular ceramic package or with built in alumin(i)um heatsink. Hope this gives you some ideas. Philip.