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

### 問題：

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

### 答案：

Collector-Emitter Breakdown Voltage - V(br)CEO

What It Is:

Collector-emitter breakdown voltage is the VC at which a specified IC flows, with the base open.  Since it's the reverse current across a junction, IC exhibits a knee shaped rise, increasing rapidly once breakdown occurs.

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

What The Display Shows:

The display shows VC on the horizontal axis, and the resulting IC on the vertical axis.  The specification is met when at the specified IC, VC 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 VC

B: Max Peak Power Watts to the lowest setting that satisfies (IC x VC)

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

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

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

F: Configuration to (Base/Open, Emitter/Common)

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

H: DotCursor 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 IC is reached

3. Compare to data sheet specifications:

Check that at the specified IC, the VC is greater than or equal to the    specified minimum