Posts: 909
Threads: 40
Joined: Jan 1970
I looked in my old HP catalogs earlier in this thread but didn't find this. But when David mentioned EduCalc, I looked in those catalogs and there is a picture of the product. I'll scan the page and email it if you want. It might be in one of the EduCalc catalogs on the Museum CD-ROMs.
Next to it is another brand NiCad charger with optional sleeves for N cells. Wouldn't it be necessary to reduce the current for N cells from what is being put out for AA cells? A PPC Journal article I referenced in another thread suggested using a AA charger with a resistor to reduce the current for the N cells. Putting a resistor in series would depend on knowing what the voltage is inside the charger. But assuming the charger was putting out 50 mA for a AA, and the voltage of a cell is nominally 1.2V, and wanting say 15 mA for the N cell, you could put a resistor in parallel to draw the extra 35 mA and it would be 1.2V/35mA=34.3 ohms and dissipate 42 mW. 34 ohms is a standard 1% value and a 1/4W resistor would do. A 33 ohm 5% resistor would draw a little more than 36 mA (with more latitude!) and would do about as well.