barfield 101-00220, Руководство пользователя

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2471F INSTRUCTION MANUAL
56-101-00220-B CH. 1
09 / 23 / 08 Page 6 of 13
2. THEORY
A transistor converter increases the battery supply to the 100, 200, and 500 volt test poten-
tials selected by the panel switch. A high performance operational amplifier increases the
impedance and sensitivity of the panel meter to measure the voltage drop across the test
probes in terms of resistance. A panel control adjusts the calibration for infinity with the
probes removed from the circuit under test. The batteries are connected to the megohmme-
ter circuit through transistor switches activated by a subminiature pushbutton on the high po-
tential probe. A single receptacle provides connection to all the test lead cable circuits, and
a shieldguard isolates the high potential lead from stray leakage resistance. A panel switch
connects the meter for testing of either of the battery circuits or for megohmmeter indication.
3. SPECIFICATIONS
(1) The electrical specifications of the instrument are indicated in Tables 1 and 2.
Table 1: Current Consumption during Resistance Measurement
Test Potential (V) Max. Draw (
µ
A)
100
±
10% 6
200
±
10% 12
500
±
10% 30
Table 2: Resistance Reading Parameters
Resistance Reading Range (M Ω )
0 to ∞
Reading Accuracy
±
10 %
Megohm Increments
Low 0.5
Midscale 17
High 1000
(2) The physical specifications of the instrument are as follows.
•
Weight: 3.8 lbs., approx. (with carrying case)
•
Size: 8" x 6" x 4.75" approx. (with carrying case)