Archived posting to the Leica Users Group, 1999/06/18
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]hello everybody, a voltage regulator is an electronic circuit which transforms an unstable input voltage (eg. from a battery) into a stable output voltage. the use of such regulators is very common in modern portable electronics but i doubt that elder CdS lightmeters have a built-in regulator. they just were not available as integrated cicuits (IC) in the sixties and early seventies. the leica CL has no regulator. if the SL has one i do not know, but if someone lends me one i can figure it out. most light-meters using CdS cells use a simple electronic (bridge-) circuit to transform the light dependent resistance of the CdS cell to a proportional voltage which is measured with an analog meter. thus the meter's readout is dependent on the voltage one uses to power the circuitry. the different batteries: silver-oxide, alkaline and mercury have different output voltages. the reasons are different electrochemical voltages of the electodes. so changing the battery type might result in a wrong meter readout. with lightmeters using a silicon photo-diode (eg. the m6) the case is different. to transform the output signal of a photo-diode (it's a small electric current) into a meter reading a more sophisticated electronic circuit is needed. and this kind of circuit will surely be independent on small variations of battery voltages. a CdS cell can easily be identified by the meander line on its surface. yours michael > -----Ursprüngliche Nachricht----- > Von: Nathan Wajsman [SMTP:nathan.wajsman@euronet.be] > Gesendet am: Freitag, 18. Juni 1999 16:28 > An: leica-users@mejac.palo-alto.ca.us > Betreff: Re: [Leica] Gossen Meters and Batteries > > ??? what is a voltage regulator, and does the Leicaflex SL have one of > those? > > Nathan > > Marc James Small wrote: > > > You can use silver-oxide or alkaline cells in place of mercury cells > in any > > device which has a built-in voltage regulator. Many European > devices have > > such circuitry, most Japanese devices do not. > > > > Marc > > > > msmall@roanoke.infi.net FAX: +540/343-7315 > > Cha robh bas fir gun ghras fir! > > -- > Nathan Wajsman > Overijse, Belgium > General photo page: http://members.tripod.com/belgiangator > Belgium photo page: http://members.xoom.com/wajsman >