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Description
Funclion
T h e i n s t r u m e n l q p p l i e s t h e p r i n c i p l e o f d e t e r m i n i n g r e s i s i o n c e b y m e o s u r i n g
th" .uir"nt throJjh on obiect with o constont ofplied voltoge. When the
u o t t o g " i s A C , t h i i p r i n c i p l 6 c o n b e u s e d t o m e o s u i e i m p e d o n c e s o s w e l l o s
resisfinces. To preveni erroneous meosurements 4.u-9 tg chonges. in.-impe-
d o n c e , t h e g e n e r o t o r o u t p u t v o l t o g e o n d t h e o m p l i f i e r i n p u t s e n s i t i v i i y o r e
c h o n o e d b y - t h e r o n q e s w i t c h , s o l h o t t h e l o o d i n g o f t h e o b i e c t o r c i r c u i i
undei test is never mbre thon 90 uVA.
The Circuir
In the ZP 2, on R-C generotor is used to supply the iest volioge. A volto.ge-
r e q u l o t o r U u t O i n o b - r i d q e c i r c u i t p r o v i d e s o c 6 n s t o n t o u t p u t . T h e p o s s i b i l i t y
of-swiichinq omonq thre"e differeni iesi frequencies fociliioies eosy identifi-
cotion of th"e reoctr've component, enobling differentiotion between C ond L,
s i n c e X c o n d X L c h o n g e i n o p p o s i i e d i r e t i i o n s w i t h c h o n g e s i n f r e q u e n c y '
The obiect to be tested is connected between two ironsformers, ond the test
uohos; is opplied to one of them. The other tronsforme.r, which hos o low
i m p e J o n c e ,
' i s
c o n n e c t e d i n s e r i e s w i t h t h e o b i e c t b e i n g m e o s u r e d . T h e
u o i f o o " i n i u c e d i n t h e s e c o n d t r o n s f o r m e r i s d e p e n d e n t u p o n t h e v o l t o g e
d r o p - d u e t o t h e c u r r e n t t h r o u g h t h e o b i e c t , s i n c e t h e o p p l i e d v o l t o g e i s k e p t
consto nt.
T o f u r n i s h t h e d i f f e r e n t v o l t o g e s w h i c h o r e r e q u i r e d f o r m e o s u r e m e n t s w i t h i n
t h e v o r i o u s r o n g e s , t h e t r o n s T o r m e r s o r e e q u i p p e d w i i h t o p s . D e p e n d i n g o n
t h e r o n o e b e i n d u s e d , d i f f e r e n t t o p s o r e c o n n e c t e d t o t h e o u t p u t i o c k s v i o
the switih. The-second tronsformei is coupled to the inpui of o four-sto-ge
o . o i i t i " r . w h e r e t h e v o l t o q e f r o m t h e o b i e c i u n d e r t e s t i s o m p l i f i e d s u f f i -
c i e i t l v t o d r i v e t h e m e t e r
- m o v e m e n t .
D u e . t o t h e p r i n c i p l e o f m e o s u r e m e n t ,
the m'eter scole is non-lineor, but becouse of severol ronges of meosurement,
h i q h o c c u r o c y i s o s s u r e d . T h e o v e r o l l r o n g e o f m e o s u r e m e n t ( f r o m 1 o h m
t o - l m e g o h m ) i s d i v i d e d i n i o t w e l v e s e g m e n t s .
On onother scole of this instrument, the bottery voltoge con be monitored.
The tester works well with power supply voltoges of 7 to 9 volts- Voltog.es
l o w e r l h o n 7 v o l t s w o u l d ' l e o d i o ' i n o c c u r o t e r e o d i n g s , b u i t h i s c o n b e
ovoided through use of the meter.
Physicol Conslruclion
I h e Z P 2 i s m o u n t e d i n o r u q g e d s t e e l c o s e ' O n t h e f r o n t p o n e l o r e i o c k s f o r
connection of ihe test cobles, ond the pushbuttons which select ihe vorious
t e s t o p e r o t i o n s ( o s w e l l o s t h e o n e s u s e d i n c o l i b r o t i o n o f i h e i n s t r u m e n t o n d
bottery testing). The meter is olso mounted on the fronf ponel.
The reor of the cose con be eosily removed by loosening lwo screws, thus
focilitoiing eosy replocement of the botteries.
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