KYORITSU 1109S User Manual

Page 23

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̶ 21 ̶

⑷ The meter pointer deflects close to full scale when the forward

current I

F

is measured. However, it hardly deflects when the reverse

current I

R

is measured.

The forward voltage of the average germanium diode measures 0.1 V

to 0.2V and that of the silicon diode 0.5V to 0.8V.

⑸ Since the maximum open circuit voltage at the low resistance ranges

is 3V (12V at X 10k range), it is possible to light up an LED having a

forward voltage of more than 1.5V and measure forward current I

F

as

well. The reading on the LI scale indicates the forward current I

F

at

which the LED lights up. The reading on the LV scale also indicates

the forward voltage V

F

For testing a large LED use the X1 Ω range. For a smaller LED

having less than 10mA IF use the X10Ωrange.

Diode Test

Fig.4

I

R

< < I

F 

N(-COM)

I

R

I

F

P(+)

Ч10

Ч1

Ч1k

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