Elenco RS500 [RS-500] Resistance Decade Box

The RS-500 resistance substitution box is a convenient instrument for determining the desired resistance values In circuits under design or test. The resistance obtainable is from 0 ohm to 11, 111, 110 ohm in 1 ohm steps. All resistors are precision 1% resistors.

Operation.

all of the resistors are wired in series. A switch on the front panel shorts each resistor. Putting the switch in the on (up) position removes the short and places the resistor across the output terminals. The two green binding posts serve as the output terminals. To place any resistance across the output terminals turn on those switches that add up to the desired resistance. For example, for 5, 071 ohm, turn on the 3K ohm, 2K ohm, 40 ohm, 30 ohm and 1 ohm switches. Before there was the Maker movement, there was Elenco.