505

The General Radio 505 Capacitor was introduced in Catalog G2 (1934) and remained available through Catalog S (1965).

The Type 505 is a secondary capacitance standard using a silvered-mica dielectric. The capacitor is installed in a low-loss phenolic case along with Silica gel desiccant then sealed with wax. The Type 505 has almost as equally high stability as the 1409 Standard Capacitor at one quarter the cost. The Type 505 is found in many General Radio instruments as a capacitance standard. It is supplied in two case sizes, the small and large.

The 505 series of standard capacitors comprises

• 505-A – 100 pF
• 505-B – 200 pF
• 505-E – 500 pF

• 505-F – 1 nF
• 505-G – 2 nF
• 505-K – 5 nF

• 505-L – 10 nF
• 505-M – 20 nF
• (505-Q – 50 nF)
• 505-R – 50 nF

• 505-T – 100 nF
• 505-U – 200 nF
• 505-X – 500 nF

Specifications

• Accuracy: at 1 kHz, ±0.5% or ±3 pf, whichever is the larger
• Dielectric: Silvered-Mica
• Temperature Coefficient: Approximately +35 ppm per degree Centigrade between 10 and 50 C. Calibration is made at 23 C, at a frequency of 1 kHz

Links

• Experimenter January 1933 describing Type 505
• Experimenter October 1957 describing Type 505

Type 505 Series of Capacitors

Type	Capacitance	Dissipation Factor	Maximum Peak Voltage	Frequency Limit for Max Volts	Leakage Resistance	Code
505-A	100 pF	0.0006	700	10 MHz	>100,000 MΩ	0505-9701
505-B	200 pF	0.0004	700	6 MHz	>100,000 MΩ	0505-9701
505-E	500 pF	0.00035	500	4 MHz	>100,000 MΩ	0505-9705
505-F	0.001 μF	0.0003	500	2.3 MHz	>100,000 MΩ	0505-9706
505-G	0.002 μF	0.0003	500	1.3 MHz	>100,000 MΩ	0505-9707
505-K	0.005 μF	0.0003	500	630 kHz	>100,000 MΩ	0505-9711
505-L	0.01 μF	0.0003	500	360 kHz	>100,000 MΩ	0505-9712
505-M	0.02 μF	0.0003	500	210 kHz	>100,000 MΩ	0505-9713
#505-Q	0.05 μF	0.0003	350	32 kHz	>100,000 MΩ	CONDENJACK
#505-R	0.05 μF	0.0003	500	100 kHz	>100,000 MΩ	0505-9718
#505-T	0.1 μF	0.0003	500	50 kHz	>50,000 MΩ	0505-9720
#505-U	0.2 μF	0.0003	500	20 kHz	>25,000 MΩ	0505-9721
#505-X	0.5 μF	0.0003	500	10 kHz	>10,000 MΩ	0505-9724

• #Mounted in large case.

Photos

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Small Case

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Large Case

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