HP Woodstock power consumption

[BusyCalc]

Hello,

do you know which is the rated power consumption of the Woodstock series?

The rear label of my HP-21 says 500 mW, but its brochure says "Battery: 350 mW derived from nickel-cadmium rechargeable battery pack".

I measured with the multimeter a current of around 95 mA with the display in 0.00, that is, around 280 mW. With the display full it'll be more, but it seems it matches a 350 mW consumption, instead of 500 mW.

Furthermore, the advertising of the Woodstocks claimed that the display size and technology was improved to save energy compared to the classic series.

I don't understand then why the rear label shows the same power consumption of 500 mW as a classic one.

(OK, some classics showed "500 MW", I suppose it wasn't 500 megawatts, hehe).

Regards.

Oscar

[burkhard]

(05-03-2019 09:16 AM)BusyCalc Wrote:  do you know which is the rated power consumption of the Woodstock series?

<snip>

I don't understand then why the rear label shows the same power consumption of 500 mW as a classic one.

Maybe the 500mW is the total current when the calculator is, filled with 8s AND the evil charger is plugged in? It all depends on where you measure the current, of course.
Why the concern about the nominal rated value, though? Do you have an interesting project planned? Do tell...

Quote:Furthermore, the advertising of the Woodstocks claimed that the display size and technology was improved to save energy compared to the classic series.

There are fewer digits than on the Classics! Hah, that's a good way to put a positive spin on what is really a bad thing.

[BobVA]

My guess: that's the consumption when plugged in, so it would have to account for charging the batteries, losses in AC/DC conversion, etc.

[BusyCalc]

Hello,

I only have been reading the HP Journals and the advertising claiming better power performance. Apart from a smaller display, the switching wasn't by induction anymore and I read in a brochure 350 mW. But the rear label shows 500 mW and I thought maybe the first units were wrong labelled.

As I needed many hours to restore my HP-21, I think I better won't do a current measurement using the evil charger, hehe. Better not to risk its brain.

It is only curiosity.

Regards.

Oscar