# How do I test a bipolar transistor for Emitter-Base Breakdown Voltage on my curve tracer?

### 問題：

How do I test a bipolar transistor for Emitter-Base Breakdown Voltage on my curve tracer?

### 答案：

Emitter-Base Breakdown Voltage - V(br)EBO

What It Is:

Emitter-base breakdown voltage is the VB at which a specified IB flows, with the collector open.  Since it's the reverse current across a junction, IB exhibits a knee shaped rise, increasing rapidly once breakdown occurs.

On the curve tracer, VB is applied by the Collector Supply.  The collector is held open, and IB is sensed at the base terminal.

What The Display Shows:

The display shows the applied VB on the horizontal axis, and the resulting IB on the vertical axis.  The specification is met when at the specified value of IB, VB is greater than or equal to the specified minimum.

How To Do It:

1. Set controls:

A: Max Peak Volts to the lowest setting above the specified VB

B: Max Peak Power Watts to the lowest setting that satisfies (IB x VB)

C: Horizontal Volts/Div to display VB between the 5th and 10th horizontal divisions

D: Vertical Current/Div to display the specified IB between the 5th and 10th vertical  divisions

E: Collector Supply Polarity to (-DC) for NPN or (+DC) for PNP

F: Configuration to (Base/Collector Supply, Emitter/Common)

G: Variable Collector Supply to minimum % (full ccw)

H: Dot Cursor ON
2. Apply power to the transistor:

A: Position the Left/Right switch as appropriate

B: Slowly increase the Variable Collector Supply % until the specified  IB is reached

3. Compare to data sheet specifications:

Check that at the specified IB, VB is greater than or equal to the specified minimum