1M ohm resistor across battery terminals - Why?

The small current probably keeps the battery impedance down, so it's ready to make a lot of current when the laser is turned on. Apparently "a lithium chloride membrane is formed over the negative lithium surface" when the battery sits around unloaded.

John

I guess they need battery voltage the instant it's turned on. Thay assume a 12-second measurement shot.

It apparently pulls around 1.2 mA when it's on.

John

I doubt they'd install that resistor if it wasn't necessary.

John

Perhaps it was meant to discharge the battery and make you buy a new device or ask for service, but somebody couldn't get the numbers right. I've seen the design solutions like that; it would be interesting to know your opinion about the moral part of this :-)

VLV

The resistor is probably there to remove the passivation layer that builds up in these batteries. I doubt Edmund would be knowingly involved in planned obsolescence.

Adding a part to make a product fail is possibly illegal... not sure. It's certainly not good business. The inkjet and toner people sometimes add a chip that stops printing before the media is totally used up, or if it's refilled. Good reason to not buy their stuff.

HP sells an inkjet printer at Walgreens for $49. I bet the ink is expensive. HP used to be a good company.

John

The ink cardridges that come with cheap printers are almost empty. Some only print a few pages. A local business recently bought a new HP color laser printer with only enough toner for 250 pages.

And a new color cartridge price? $85 for each CYMK (HP CP2020)

Cheers

HP CP2025 with a built in duplexer, for double sided printing on a ethernet ready network or USB printer. It was about $250 for a full set of standard cartridges, on sale. The printer was $349.99, on sale. It replaced a very old & tired Minolta

Interesting item: Yesterday I was at Costco looking at inkjet carts. The replacement carts (HP brand) for my HP 6000 officejet color printer are priced at almost 2x the cost of what I paid for the new printer that had ink carts included. The carts were that same capacity.

This is a rip off if I ever saw a rip off. I bought a refill kit from Ebay for about $25 that has enough ink to refill them at least ten times.

The printer makes clean prints however it isn't very friendly.

Wilby

Heh. :) I used to reink ribbons for dot matrix & impact printers. Refilling Inkjet cartridges is a whole lot easier and cleaner.

I once got a really great deal on a printer on ebay; the cartridges cost more than the whole printer! ;-)

Cheers! Rich

Thanks for the info; I didn't know about passivation of Lithium batteries.

Isn't it the same thing as disabling product features that are already there?

VLV

Buy a printer from a company that isn't a *well* known rip-off.

I don't think so. If a feature involves IP or just writing a lot of code, as things tend to do nowadays, it makes sense to charge for it. Otherwise, all software would be free.

Further, it often makes sense to have a single build chain to compile (code or FPGA) the whole thing, including all the features. So enabling features for money is reasonable. If you make it too easy to crack, some people will.

A lot of Microsoft products are crippleware.

Deliberately making a product wear out is a different matter. Microsoft does that too, in a sense.

John

Who would that be?