The total resistance isn't fixed since it will go up and down depending on how many controllers are plugged it, as the CD seeks, the volume level changes, etc. You don't need to know it though. Unless the system shorts internally, its incapable of drawing more amperage than designed. The amount of current flowing through the IFU will be determined by the resistance (same as when the IFU was built) and the voltage (same between the RS and OEM PS). Since the original supply was rated at 1450mA, then we know that the maximum expected draw from a healthy PCE is the same or less, meaning that the minimum resistance of said unit is 6.2Ω. In reality is actually much more than that. I've run my Duo R off a 240mA PS and it actually ran fine except when the CD moved. Then the display went dim and bad stuff started happening (ie: it was outdrawing the PS I was using, and voltage was dripping below 9V, probably below 5V).
Likewise, you can put the 12V battery from a big GMC diesel van in your 1984 Honda Civic (assuming you could physically fit it under the hood) with no problems at all, even though the amperage on the van battery is probably 6 times what the Civic needs.
Also, the difference between the Radio Shack and OEM adaptors is 50mA, which is below production variations, from my experience, anyway.
I think I'm not doing a good job of explaining it, but its really a second nature concept for me as I learned this stuff in the 8th grade and use it every day. I'm sure there is a Flash animation or something on the internet (probably using a garden hose as an analogy) that does a great job of explaining it.
Topic: pc-engine+CD power adapter question (Read 2073 times)
