S P E C I F I

Range: 0.5 to 2,000,000 megohms at 500 volts and to 200,000 megohms at 100 volts. There are six decade steps selected by a multiplier switch.

Scale: Each resistance scale up to 500,000 megohms utilizes 90 % of the meter scale. Center-scale values are 1, 10, 100, 1000, 10,000, and 100,000 megohms for 500-volt operation.

Accuracy: From ±3% at the low-resistance end of each dscade to +12% (accuracy to which the scale can be read) at the high-resistance end up to 50,000 megohms. There can be an additional ±2% error at the top decade.

Voltage on Unknown: 100 or 500 volts, as selected by switch on front panel. Indicator lamp is when 500 volts are applied, provides a warning to the operator, for, although the instrument current itself is not dangerous, a charged capacitor on the terminals is dangerous and could be lethal.

One change repeatedly asked for was the new, 100-volt test voltage, which is a standard for many measurements. This replaces the 50 volts provided on the older instrument. The accuracy is the same for both 100 and 500 volts, in contrast to the poorer accuracy on the 50-volt range of the older model. Internal changes include the use of semiconductor rectifiers and a "premium" tube in the meter circuit, whose low grid current improves the stability of measurements of very high resistances.

Our survey indicated that over 80% of the instruments were used for insulation resistance measurements, and the rest were used to measure volume and surface resistivity or high-valued resistors. The insulation resistance measurements were on cables, capacitors (leakage), transformers, connectors, relays, printed circuits, motors, and switches. With the new model these measurements can be made with even more ease than in the past.

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