OPERATING INSTRUCTIONS 1 Identification of Controls

The lower group of controls on the panel operate the internal variable standards. The right dial is calibrated directly in ohms resistance, this dial is marked R. The lever switches immediately above the dial are the resistance adder switches. When the adder svritches are in the 0 position they are inactive. When the switches are in other positions the values indicated a3 e added to the reading of the R dial to obtain the resistance of the load. The two adder switches may be used in any combination of settings to extend the resistance range of the bridge to 1000 ohms. 

The left dial is calibrated in ohms of reactance at 1 mHz and marked X/FMC. The reactance adder switches are immediately above this dial. 

They can be used in combination to extend the reactance range (at 1 mHz) to 900 ohms. When measurements are made at frequencies other than 1 mHz, the reactance reading must be corrected by multiplying the value read (including the adders) by the frequency in megahertz. For example, if measurements are made at 1.5 mHz and the total of the adder switch and the dial reads 250 ohms, the actual load reactance will be  

The switch marked L -C between the two dials in the center of the panel is for the selection of positive or negative reactance loads. If the load is inductive, the switch must be in the position to obtain a null, and the reactance values read from the reactance dial are +j values. A bridge null can be obtained only when the switch is in the correct position. 

Immediately to the right of the meter is a switch marked AMP. IN/OUT. When this switch is in the Out position the detector circuit is connected directly to the bridge and the sensitivity controls, marked SEN., controls the meter sensitivity. When it is in the AMP IN position an integrated circuit RF Amplifier is inserted before the detector circuit. This amplifier increases the internal detector sensitivity for measurements in low power circuits. 

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