HP 410C manual Prf, Negative Pulses

TM 11-6625-1614-15

Section III

Paragraphs 3-28to 3-34

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

Suppose, for example:

t 1 = 10 microseconds

t 2 = 990 microseconds

K	=	0.55
PRF	=	1000 pps
To find K, assuming			=	2	kilohms	and	tl=10micro -
s e c o n d s : R o /tl = 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 /tl were	greater	than 1,	multiply	the
X	and Y	axes by 10,	and use	the curve	marked	”Ro/
t1 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

(t2) and	a pulse repetition frequency (PRF) of 1000 pps,
tl would	be 990 microseconds. Thus T o/t1 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.

3-31. MEASURING RESISTANCE (Figure 3-7).

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