Both my DT402D throttle and the DSO138 scope can use a 9 v source, but 9 volts just is not an easy voltage to achieve with today's batteries. I have an 8 pack of 1.2 volt AA cells but they are a pain in the neck to recharge since I can only do 4 at a time. I have some 8.6 volt rechargeable "9 volt" batteries but they are right on the edge of not having enough voltage and they only have about 150ma. There are some nice 3.6 volt cells (18650) that I could use 3 in series then a regulator to get down to 9, but that's not that appealing either. So I'm wondering what others are doing? The scope has the typical socket for power and on the DT402 throttle I took a 9 volt battery apart and put a pigtail on it that then fits the 9 volt battery slot in the throttle so no mods were made to the throttle. The same socket is on the DSO138 scope so my 8 cell pack can power either.