32
In the circuit of Fig. 3 it may be noted that R1 is in parallel with a low-
value resistance (the one from the micro-ammeter) therefore its influence
is reduced during reading.
Through resistance R2 circulates a current which is not passing through
the meter and consequently does not affect the reading. In fact, current
through R2 originates a certain error, since it creates an additional voltage
drop in R1 which was not regarded during megohmmeter calibration. As
regards the practical use of megohmmeter, it shall be considered that if
R1 and R2 are higher than 100 M
Ω, any value of Rx will be measured
with an insignificant error. For example: Let us consider Rx = 3000 M
Ω
and R1 = R2 = 100 M
Ω, the reading without using the GUARD terminal
would be 187.5 M
Ω, which is quite wrong. On the other hand, if the
GUARD terminal is properly used, we would have 3000 M
Ω.
Summary of Contents for MD-5060 Series
Page 24: ...26 8 Printer Printing sample...
Page 32: ...34 NOTES...
