Keithley 6220 Reference Manual page 154

5-34 Delta, Pulse Delta, and Differential Conductance
The affects of heating can be eliminated by not performing the measurement at
point C (low pulse). For this 2-point measurement technique, Pulse Delta is calcu-
lated as follows:
PulseDelta
Measurement units
The fundamental Pulse Delta measurement explained above is in volts. The read-
ing can instead be converted into Ohms (W), Siemens (S), or Power (W). Details
on selecting
With Ohms or Siemens measurement units selected, the reading is calculated as
follows:
W = V/I
S = I/V
The calculation for power depends on the power reading type that is presently
selected (Peak or Average) and is discussed as follows.
Peak power and average power
With Power units selected, a Pulse Delta reading can be expressed (and dis-
played) as a Peak power reading or an Average power reading. Peak power is the
default setting.
Figure 5-9
using the basic power equation (W = IV), where I is the high pulse current (I-High)
and V is the calculated Pulse Delta voltage.
The average power over the entire Pulse Delta cycle can calculated by factoring in
the duty cycle. Duty cycle is the percentage of time that the pulse is high during
the Pulse Delta cycle. For example, assume the period of the Pulse Delta cycle is
1ms. If the pulse is high for 0.25ms, then duty cycle is 25%.
Mathematically, duty cycle is expressed as follows:
Duty Cycle (in %) = Pulse Width / Pulse Interval x 100
Where: Pulse Width = Time that the pulse is high.
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 - TestEquipmentDepot.com
⎛ ⎞
2B 2A –
• – ( )
-------------------- -
=
⎝ ⎠
2
( ) 2 0.01 (
2 10.01 –
= -------------------------------------------------
2
20mV
= --------------- -
2
10mV
=
"Measurement units" are provided on
shows how Pulse Delta voltage is calculated. Peak power is calculated
Pulse Interval = Time period of the Pulse Delta cycle.
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Model 6220/6221 Reference Manual
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Section 5 topics
5-16.