Charger for Classic


Hi everybody on the Forum.

Is there the possibility to build a charger for a Classic from scratch?

Would it be possible to use one of the many chargers around for other devices?

And waht about the connector to the calc?

I couldn't find a lot on this matter over the Museum (OK, batteries are well covered)

so any suggestion would be very welcome.

Thank you all.




Why? There are plenty of them on the market. If you send me an e-mail I can offer you one with European plug and voltage, working for sure.

Regards, Walter


Hello Giancarlo,

The charger for a classic is actually two power sources in one...
A constant voltage source of about 5VDC to run the calculator,
and a constant DC current source to charge the batteries (which measures about 12VDC unloaded as I recall).

Building one, while not impossible, would certainly be a home science project.
I would tend to agree with the previous responder...these charger are widly available on E-bay for a reasonable cost.

Best regards, Hal


Widely available on Ebay? Not that I've seen.

I'm searching for a couple of these myself and haven't seen one offered alone in a week and a half.

They are offered with a classic HP, but I haven't found them solo.




The article forum contains the schematics for the charger:

Tony D.'s article


Building the electronics is fairly trivial... building the connector is not. Bite the bullet and either buy one on Ebay (hint, it is often more cost effective to buy a classic with charger than a bare charger. Warning: a LOT of chargers have damaged connections in the molded rubber plug) or else charge the batteries external to the calculator.

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