Model 4342A Section III
Paragraphs 3-73 to 3-75
Series Connection Measurements
3-73. SERIES MEASUREMENTS. C. Short-circuit the unknown (series con-
nection terminals) with a heavy (low
Note impedance) shorting strap.
In the following series connection d. Adjust L/C dial and AC dial controls
measurement procedures, set 43424 for a maximum Q meter deflection.
Q RANGE as appropriate unless Note sum of the C dial and AC dial
specifically instructed otherwise. readings as Cl and panel meter read-
ing as Ql.
3-74. Low Inductance Measurement.
e. Depress AQ button and adjust AQ ZERO
3-75. Measurement of small inductors at (COARSE and FINE) controls so that
relatively low frequencies can not be made meter pointer indicates zero (full
directly at the measurement COIL terminals. scale) on AQ scale.
However, by using an external high Q capaci-
tor (such as the 16462A Auxiliary Capacitor) Note
connected in parallel with the tuning capa-
Press AQ button to release AQ func-
citor, resonance can be obtained at the de-
tion and recheck for correct reso-
sired frequency. A second method, which is nance. Again depress the AQ button
explained here, is the series method. This and recheck for hQ zero indication.
method is recommended for measuring low value
inductors without using an external capacitor Disconnect the shorting strap. Again
f.
(but with an external inductor).
resonate the measuring circuit by ad-
justing L/C dial and AC dial controls.
When the measuring circuit is resonated using
Note sum of the C dial and AC dial
a reference inductor, the test inductor readings as C2 and panel Q meter AQ
placed in series with the reference inductor reading. If meter pointer scales out
will lower the tuning frequency. To restore
at the left end of the scale (AQ full
resonance at the measurement frequency, the
scale), reset the function to normal
tuning capacitance must be reduced. The in-
Q measurement. The difference in Q is
ductance of the unknown inductor can be
calculated from the two Q values as
determined from the relationship between the
AQ = Q1 - Q2.
tuning capacitances at the same frequency.
Note
After the sample is connected, quality factor
and equivalent series resistance can also be
This procedure (steps c, d and f)
calculated from a reduction of panel Q meter permits the unknown component to
indication. Proceed as follows: be physically connected even
through it is electrically out of
a. Depress the appropriate FREQUENCY the circuit, and eliminates pos-
RANGE button and set FREQUENCY dial sible errors by maintaining the
control for the desired measurement relative positions of the refer-
frequency.
ence inductor and unknown component.
b. Select a reference inductor which Inductance of the unknown inductor is:
g.
allows the measuring circuit to reso-
nate with a tuning capacitance of ap- l,s = (zic;cf2) (H) . . . . . (eq. 3-35)
proximately 400pF. Connect unknown
inductor in series with the reference
inductor (between measurement LO Where, W = 2~ times the measurement
terminal and low potential end of the frequency.
reference inductor) and to measurement
COIL (HI and LO) terminals. Q value of the unknown is:
Q1Q2CC1 - C2)
Note Q= "....... (eq. 3-36)
Cl (21 - C2Q2
If 16014A Series Loss Test Adapter Where, 42 = Ql - AQ
is available, attach it to measure-
ment COIL terminals. Connect the Equivalent series resistance is:
reference inductor to appropriate
terminals of the 16014A and unknown
Rs = ($$I Q1 - 42 (n) . . . . . (eq. 3-37)
inductor to 16014A series connection
terminals. ~CI QI Qz
3-23 |
ACEC
HEWLETT-PACKARD
