Play Meter

+! () a·
]O v t- - -
-,--------T"'""--
/ II
v,
41 5m V - --t
-
1.15•
1--+--------4
0.875 •
Fig. 15-3. Practical JF ET - NPN Schmitt Trigger Design .
Fig. 15-4. Output Characteristics of the Schmitt Trigger of Figure
15-3.
To insure T 1 is off,
EXAM PLE 1 :
Gi ven th e J F ET-NP
c hmitt Trigge r in F ig. 15-3 , co mput e
th e vo ltage limits fo r the hys tre is ba nd and th e va lues of th e
o utput vo ltage. A u me the device have th e pa ra me te r · listed
belo w
0.6v +
= OmA
Y 8 , (o ff) (aJ 1 0
= 1.0/J.A
= 300n
= l .:!v.
22 · 1 o- 3
20v
•
7.292
0.6v + 0.06v
660mY
J FET : (T ,)
>
>
= '2m A
fo rT , o n and T 1 o ff,
Y, ,
0. 75v
>
300 · 1 o- 3
PLAY METER. October 1. 1985
20v
557mY
ForT, off and T 1 on ,
Y,,
470 ( 20v) 1 o- 3
7.292
Y, l
= 1. 29 v
Y 0 (on)
= [470+22
7.292
Y 0 (on)
= 1.35 v
= 0.6v
J · 10-
3
•
20v
Fig. 15-4 shows the output characteristic which illustrates a
hystresis band of about 415mY. This circuit can be quite useful
with photocell devices since the gate circuit will not load the
photocell circuit.
LET US BE YOUR DRUMMER!
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10.77
0.55 7v
p : (T ,)
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I ]9v
v,
PLACE YOUR ADVERTISEMENT TODAY!
CALL: 504/488-7003
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