HP (Hewlett-Packard) 410C ユーザーズマニュアル

TM 11-6625-1614-15

PRF is the pulse repetition frequency in pulses per
second (pps).

Suppose, for example:

t 

1 

=

t  

2 

=

K =

PRF =

10 microseconds

990 microseconds

0.55

1000 pps

To find K, assuming

/

= 2 kilohms and 

t

l=10micro-

s e c o n d s :  

R

o

/

t

l 

= 2 10° = 0.2. Location 0.2 on the

X axis of the graph shown as Figure 3-6, and reading
K where X and Y axes intersect the unmarked curve. If

the ratio of 

R

o

/

t

l 

were greater than 1, multiply the

X and Y axes by 10, and use the curve marked ”R

o

/

t

1  

and K each X10”.

Solving the expression for the multiplying factor,

Model 410C

3-28. NEGATIVE PULSES.

3-29. In the case of a 10 microsecond negative pulse

(

t

2) 

and a pulse repetition frequency (PRF) of 1000 pps,

t

l 

would be 990 microseconds. Thus 

T

o

/

t

1 

would be

approximately 0,

and from the graph it is seen that

K is approximately 0. The expression would then

reduce to

3-30. It can be seen that in the case of negative pulses
of short duration much smaller readings will be ob-
tained for an equivalent positive pulse. As a result,
large multiplying factors must be used and unless the
pulse voltage is large, these measurements may be
impractical.

3-32. Before making resistance measurements, power
must be removed f rom the circuit to be tested. Also,
make sure capacitors are discharged to eliminate any

residual voltage.

3-33. MEASURING DC NANO-AMPERE CURRENT
(Figure 3-8).

3-34. The Model 410C can be used to measure nano-
ampere leakage current in transistors and diodes. The

three most sensitive DC voltage measurement ranges
are used to measure DC nano-ampere currents.

.

.

3-4