BK Precision 501A Instruction Manual Download

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Figure 10. Typical Test of an NPN Transistor

match the transistor type. Slowly increase the

SWEEP VOLTAGE control until a complete dis

play appears on the oscilloscope screen. If the

type of the transistor is undetermined, do not

exceed the "fast set-up" marker of the SWEEP

VOLTAGE control (20V) if a display does not

appear; return the SWEEP VOLTAGE to zero,

reverse POLARITY, and slowly increase the

SWEEP VOLTAGE again until a complete dis

play appears.

5. Adjust the centering controls of the oscilloscope

to properly position the family of curves. For

jNPNj

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ADJUST OSCIL LOSCOPE CENTERING

CONTROLS TO PLACE START OF

ZERO REFERENCE STEP HERE.

NPN transistors, the display should be posi

tioned so the curves start at the left hand bot

tom corner of the graticule scale. For PNP

transistors, the displ

should be positioned so

the curves start at the right hand top corner of

the graticule scale (see Figure 1 I).

6. If the transistor is shorted there will only be a

vertical trace (see Figure 12). The current (ver

tical trace) increases sharply to the current limit

ing value determined by the curve tracer. There

is no family of curves, since the value of base

current applied has no effect.

ADJUST OSCILLOSCOPE CENTERING

CONTROLS TO PLACE START OF

ZERO REFERENCE STEP HERE.

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Figure 11. Characteristic Curves of NPN vs. PNP Transistors

Summary of Contents for 501A

Page 1: ...Model 501A Semiconductor Curve Tracer...

Page 2: ...ave helped provide better and faster service techniques Close contact has been maintained with the manufacturers of consumer products which our test units will be checking and trouble shooting Key per...

Page 4: ...PPLICATIONS 14 Testing Bipolar Transistors 14 NPN vs PNP Transistors 14 CURRENT GAIN MEASUREMENT 14 DC Current Gain DC beta 15 AC Current Gain AC beta 15 Summary of Transistor Current Gain 16 Current...

Page 5: ...4 IC 5 6 7 8 Q 1 Q 2 3 Q 4 Q 5 6 11 12 Q 8 9 10 SW 2 SW 3 SW 4 SW 5 11 72 488 113 9 002 8 DESCRIPTION CAPACITORS B K PART No 1000 fd 35 Volt Electrolytic Capacitor 022 001 9 015 100 fd 25 Volt Electro...

Page 6: ...SJ TEP l OLA l lIt S lfilJC T TO f W f 0 1T N SOC tt SCLtCTOR SET TO lh Hr l OSIHO t I VUtf J 1 S NSITl TV SW l N l TO jl l Ai IV u 01 i t S1 l I IO i G l l G iT SO J tl T Rw t C t I 1 Ill 1S 1 IW 1 4...

Page 7: ...er general purpose oscilloscope is satisfactory as long as it has external horizontal facilities and is DC coupled The B K Models 1440 1460 and 1465 Oscilloscopes are ideal companions for the Model SO...

Page 8: ...7 8 17 16 15 14 13 12 II 10 9 18 0 0 Figure 1 Controls and Operator s Facilities 2...

Page 9: ...rts base to emit ter terminal for measuring collector emitter leakage cur rent with O Volt base bias Selects the gate voltage step value for testing FET s The unit automatically generates gate voltage...

Page 10: ...sitions of the STEP SELECTOR switch constant voltage steps are generated for testing FET s Five selections from 05 to 1 volt per step are offered The polarity of the voltage steps is inverted in relat...

Page 11: ...rent thru the semiconductor being tested and the hori zontal divisions must accurately represent the sweep voltage applied to the semiconductor being tested that is the oscilloscope must be calibrated...

Page 12: ...of reading the horizontal voltage is available by connecting the sweep voltage output of the curve tracer H jack to the horizontal input of the oscillo scope This method will produce a horizontal trac...

Page 13: ...Ground the vertical input if desired Adjust HORIZONTAL GAIN so 4 Connect a test lead from the H jack of the curve tracer to the horizontal input of the oscilloscope 5 Set the SWEEP VOLTAGE control to...

Page 14: ...aneously switched from one semiconductor to the other The SOCKET switch may also be used to start and stop the test of the semiconductor merely activate the empty socket to stop the test This allows c...

Page 15: ...ied for testing zener diodes leakage of signal and rectifier diodes and inverse peak breakdown voltage Forward bias characteristics show voltage drop across the diode junction and resistive or open co...

Page 16: ...t r 3 2ti l p pr t r 1 l 0 2 3 6 7 8 9 10 ADJUST OSCIL LOSCOPE CENTERING CONTROLS TO PLACE START OF ZERO REFERENCE STEP HERE NPN transistors the display should be posi tioned so the curves start at th...

Page 17: ...f the display Increasing the setting widens the display and may cause the display to go off scale Decrease and increase the setting of the control and note the effect upon the display If increasing th...

Page 18: ...s displayed on the VERTICAL SENSITIVITY range being used If the setting is too high some of the curves may reach the current limiting value and be superim posed on each other causing less than five cu...

Page 19: ...ideal for making contact to transistors mounted on P C Boards Refer to the In circuit Probe section for more information When performing in circuit tests use the fast set up markers on the 501 front...

Page 20: ...turn the VERTICAL SENSITIVITY to the 1 mA Div position after each test so that the next test begins with full protection NPN vs PNP Transistors As described previously in the Typical Test section the...

Page 21: ...ent point Simply approx imate the percentage of distance between the curves above and below the poin use it as a percentage of one step to obtain total base current when added to the number of current...

Page 22: ...to gether at higher collector current Each base current step has precisely the same amount of increase which should cause the collector current curves to be separated by equal amounts if the gain wer...

Page 23: ...d does not introduce distortion If 6 10 s are imbalanced distortion will be intro duced due to this non linearity The greater the im balance the greater the distortion The distortion measurement can b...

Page 24: ...would be destroyed by the test Figure 21 shows a typical family of curves with the sweep voltage set high to cause collector break down In the examples shown in the figure break down occurs at a coll...

Page 25: ...t portion of the family of curves in the area of low collector voltage and current below the knee of each curve Notice that the knee of each curve occurs at approximately the same collector voltage re...

Page 26: ...tance The transistor s output impedance or collector resistance is the reciprocal of its output admittance and is measured in ohms It may be calculated by transposing the current and voltage values us...

Page 27: ...collector voltage at various base currents FET curves are a graph of drain current vs drain voltage at various gate voltages FET breakdown voltage may be observed and measured by the same method used...

Page 28: ...e MOS FET s can be damaged by a voltage transient from a static charge carried by the person handling the device Safeguard against such damage and discharge any static charge by touching ground with o...

Page 29: ...ty may be determined by the same method as desribed for transistors if the spacing between curves is equal the FET is linear Pinch Off Vp Voltage Measurement An important characteristic for depletion...

Page 30: ...scale GERMANIUM SILICON 1 100 80 Io ma 0 5 1 1 5 VF volts FORWARD BIAS 2 2 5 When testing diodes only one curve is displayed not a family of curves as displayed for transistors and FET s The forward b...

Page 31: ...OLT j _ _ 2 I I I ZENER I i 1 1 filgl i I i l j i I I I H i_ i t lJ__tH 10 a 6 VR 4 2 o SHARP ZENER KNEE To obtain the most accurate voltage reading pos sible calibrate the full scale oscilloscope hor...

Page 32: ...y The curves C E appear quite close together and careful observation may be required to distinguish the individual curves It may be helpful to spread out the display by in creasing the horizontal sens...

Page 33: ...e Any anode current at anode voltage below the firing point is forward leakage current and can be read directly from the display Reverse Blocking Voltage Reverse blocking voltage is the maximum revers...

Page 34: ...age and increase the de bias supply until the SCR switches on Measure the value of gate voltage at which switching occurred 2 Set the de bias supply to a specified gate volt age and increase the sweep...

Page 35: ...I I 1 Vp t I I I I 10 I 1 i I i 1 L 1 1 I 1 I 5 I i I 1 5 J MA I I l l Ip peak current start of tunnel region Iv valley current end of tunnel region Vp peak voltage start of tunnel region Vv valley v...

Page 36: ...y soldered wires short TP30 TP31 and TP32 to the S Volt line on the PC board 4 Attach a digital voltmeter to TP29 and turn on AC power to the unit 5 Adjust the CALIBRATE pot R36 for a reading of 3 50...

Page 37: ...board It is most important to follow the explicit control setting and set up pro cedure as given in the notes column in order to obtain the illustrated waveforms Point by point sig nal tracing with a...

Page 38: ...VAC 50 IOkl l IG H VOLTAGE ECONO Ut f aiJitllttN1 u nsim R Sl l0ll S 6 SEL CTOR to a countdown chain composed of 3 flip flops within two IC packages IC3 and 4 The second flip flop of IC4 is not used...

Page 39: ...through the SOCKET SELEC TOR to the desired test socket RIGHT or LEFT The higher voltage secondary of the power trans former is full wave rectified by a diode bridge DI through D4 to produce a 120Hz s...

Page 40: ...se new from an authorl r ed B K distributor Our obligation under this warranty is limited to repairing or replacing any product or component which we are satisfied does not conform with the fore going...

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