A question about alternative power supply for hp41 series

[wojtek]

(02-24-2016 12:27 PM)Artur - Brasil Wrote:  Hi, I found one converter, in the format of a very small module. It's rated from 2V to up 18V!
Great for my pourposes! I'll receive it these days and will work on what I'm saying: having a portable calculator with simple batteries in it.

Me too :-) I ordered 3 different converters, still waiting for the package to arrive.
At the moment I have only one converter, which gives stable 5.5V with input in 0.8 to 1.5V range
The closer look at the shape of the output waveform on a scopemeter showed that it is of ramp shape of about 20mV peek-to-peek at 5.5V level, about 1kHz frequency, but the single capacitor some 10 uF should do.
You better inspect the waveform on an oscilloscope.
Important is how the converter will behave under very small load, some 20 uA, necessary to provide power for continous memory of 41c, will it start at all?. I checked mine and it seems to be OK