General Radio 1409-F Highlights
The GenRad 1409 Standard Capacitor is series of highly stable, cost-effective capacitance standards. With low temperature coefficient, low losses and these standard capacitors come in a wide range of capacitance values from 1 nF - 1,000 µF. Up to 1 µF, the standard capacitors are constructed of fixed mica capacitors of very high stability for use as two- or three-terminal reference or working standards in the laboratory. From 1 µF to 10 µF the units are made of hermetically sealed polystyrene for 10 _F. Above 10 _F the capacitor is hermetically sealed polycarbonate.
Typical capacitors, observed over decades, have shown random fluctuations of less than + 0.01% in measured capacitance with no evidence of systemic drift.
The capacitors are made out of ≤1 µF silvered-mica and foil, spring-held in a heavy metal camp for mechanical stability. The units are selected for low dissipation factor and are stabilized by heat cycling. They are housed in cast aluminum cases, along with silica gel which provides continuous desiccation. These cases are sealed with high-temperature wax. A well is provided in the wall of the case for insertion of a dial-type thermometer. Three jack-top binding posts are provided on the top of the case, and removable banana plugs on the bottom, for convenient parallel connection without error.
A well is provided in the wall of the case for insert_ing a dial-type thermometer. For convenient parallel connection without error, three jack-top binding posts are provided on the top case, with removable plugs on the bottom.