Gary I am familiar with the lock mechanism you are referring. John is correct, it is a poor design. They have traded off the convenience of the snap in 9 V battery to do a job it was never intended to do, activate a solenoid. However it is not entirely the manufacturer's fault.
In this day and age I see an environmentalist behind many problems. When batteries are subjected to high currents gas bubbles form around the electrodes, partially insulating the electrode and raising the effective internal resistance. This is called polarization. The manufacturers have their trade secret depolarizing compounds they add to the battery. One of the elements they use is mercury. You will also note some manufactures advertise their batteries do not contain mercury. 2+2=4. Fred Townsend DC to Light John Woodgate wrote: > In message > <d500012385dca64883637ab4ccf491e3016b2...@ms-cda-02.advanced-input.com>, > dated Thu, 8 Apr 2010, "McInturff, Gary" > <gary.mcintu...@esterline.com> writes: > >> I think car batteries have an additional rating of cranking amps is >> there something similar on 9 volt batteries? What?s the root cause in >> performance difference ? internal bulk capacitance? The circuit logic >> would determine the max current flow out of the battery so the >> battery type shouldn?t matter ? right? Maybe the R of the logic and >> the C of the battery changes the di/dt? > > > It's not capacitance (*) but internal resistance. The short-circuit > currents of modern 9 V batteries are of the order of 100 A, and have > to be tested under precautions against injury due to explosion. These > currents are so far in excess of the recommended discharge currents > that no-one is normally concerned about them. But in some > electromechanical applications, the ability to briefly deliver a very > large current is crucial. Not good design. > > (*) Even though the equivalent capacitance may be of the order of 1 F, > the internal R is obviously milliohms, so the RC time constant is only > milliseconds. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
