Tektronix 576 - Page 38

Operating Inst ru ctions-Type 576
R B2B1
T he interbase resistance can be measure d by p lacing t h e base2 lea d in t he collector
terminal of t h e test sock et and t he base, lead in t he emitter terminal . L eave t h e emitter
lea d at t h e d evice o p en an d apply voltage across t he two bases wit h t he VA R IA BLE
CO LLE CTO R S UPPL Y control .
SI L ICON CO N T R O LLE DRE CTI F I ER S (SC R
s)
R equired Typ e 576 Control Setti n gs
IF
vs . VF for d iffere n t
values of VG
ΡΕΡ
Η
Ο
R
D
ι V
Ρ
Turn-on
2- 30
Some Commo
n M
easurements
T he gate voltage or current at w h ic h t he d evice turns on can be measure d by a pp lyi ng α
s p
ecified voltage between t he a n ode and cath od e terminals usi n g t he VA R IA BLE CO L -
LE CTO R
S UPPL Y co n trol and app lying current or voltage ste p s in small increments to
t he gate with t he AMPL IT U D E switc h .
F orwar d B loc k ing V oltage

To measure t he forwar d bloc
k ing voltage, set t he Terminal Selector switc h to B AS E
TERM OPEN
(or S H O RT de pen ding on t h e s p ecificatio n ) and turn t h e VA R IA BLE
CO
LLE CTO R S UPPL Y control cloc k wise u ntil t he d evice switch es to its low im p e dance
state . T he voltage at w h ic h switc h ing occurs is t h e forwar d block ing voltage .
H ol d
ing Current

H ol d ing current is measured in t he same man n er as forward bloc k ing voltage . H olding
current is t h e minimum current con ducted by t h e d evice, w h ile o p erati n g in its low
im ped ance state, with out t urning off .
R everse B loc k ing V oltage

T he reverse bloc k ing voltage is measured t h e same way as t he forwar d block ing voltage
except t h at t he P O L A R ITY switch is set to -( ΡΝΡ ) .
Co n trol R e q uired Setting
H O R IZO N TA L COLLECTOR
PEAK P O WER W ATTS L ess t h an maximum p ower rating of device
POLARITY +(NPN)
ST EPS P resse d w h en using
low
gate voltage or
current
PUL S E D ST EP S P resse d w hen using h ig h gate voltage or
current
Terminal Selector EM ITT ER GR OUN D E D B AS E T ERM STEP
G EN