
6.OPERATIONS
6-1INDEPENDENTOPERATION
(1)The(+)terminalorthe(-)terminalistobeconnectedalwaystotheGND.
Terminal(GND)withshortcircuitbarasanaccessor
shouldbeconnectedasshowni
Fig6-1.
Whenpositiveoutputpolarityisrequired.
-GND+
SHORTCIRCUITBAR
(2)ConnecttheACPowercordtothepowersourceofthespecifiedvoltage,andturnon
thepowerswitch.
(3)Tosettheloadvoltage,slowlyturnthevoltageadjustingknob(5)caorseclockwise
withnoload,whilewatchingtheamperemeter.
Theknob(5)isforcoarseadjustment,andtheknob(4)isforfineadjustment.
(4)Loadcurrentsettingisusedforlimitingthecurrentappliedtoadevicetobetestedat
aspecifiedpowerortoprotectthedevicefromtheovercurrent.
Tosetthecurrent,connectthe(+)and(-)terminalabyathickleadwire.
Slowlyturnthecurrentadjustmentknob(3),andsetthecurrentwhilewatchingthe
amperemeterindication.
Atthistime,setthevoltageadjustmentknob(5) f u l l c o u n te r c l o c k wi s e a n d s e t th e
whitemarkoftheFINEadjustmentknob(4)atmiddle.
Theminimumcurrentthatcanbesetisasfollows.
GP-4303D/A:Approx.200mA~3A GP-4185D/A:Approx.350mA~ 5A
Aftersettingalimitingcurrent,removetheshortcircuitwire.
Thensetthevoltagetoarequiredvoltagelevel.
(5)Aftercompletingtheaboveprocedure,watchthepolarityofadevicetobeapplied
andusetheinstrument.
Ifthevoltmeterindicationbecomeslessthanthessetlevelforadefectofadeviceto
betestedorforanyotherreason,theovercurrentprotectioncircuitisactivated,
resultinginswitchingintotheconstantcurrentoperationfromtheconstantvoltage
operation.
Whentheinstrumentistobeusedintheconstantvoltageoperatingcondition,setthe
currentadjustmentknobfullclockwise.
Inthiscasetheshortcircuitcurrentis3A+10%fo rth e GP - 503, 5A +10% for th e
GP-305/505,and10A+5%fortheGP-3010.
Fig.6-1
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