Document dD5noOp8xD6mbLe17YY9V1Dmq

moms Into .cebekal cckpany o f aiabama INSPECTION DEPA'RTVTnwi* '- : DETERMINATION Og DIELECTRIC CONSTANT 07 LIQPID AROCLORS AT 100C. A. Circuit Arrangement for Dieleotrie Constant. } Power Souroe: 6 volt plat bat y'! from 1000 ops. tery with Audio Oscillator, Gene oscillator ral Radio Type 21JB giving fre quency of 1000 ops. -^ymrrr- Capaoity Bridge: General Radio Type 216. Telephone: Head phones with two stage amplification. Ca: Variable Air Condenser, 1500 MMF capaoity, G.R.Type 246-L. Cp: Precision Condenser (variable air), 1500 MMF capacity, G.R.Type 222-L. Cx: Condenser of about 200 MMF air capacitance, arranged so that space between plates may be filled with liquid dieleotrie under test. The "unknown" oondenser. Bridge Balance: With resist ances N and M equal and the bridge in balance, then Ca - Cp + Cx B. Procedure for Measurements. 1. Since dielectric constant is the ratio of capacity of a con denser using the substance under test as the dielectric to the capac ity of the same oondenser using air as the dielectric, the measure ments to be taken are capaoity measurements. Capaoity is measured by a substitution method using a modified Wheatstone Bridge. 2. Determine eapaoitanoe of Cx with air as dielectric by balanc ing Cx and Cp (in parallel) against Ca. Then disconnect Cx and with out changing Ca, adjust Cp until balance is again obtained. The difference in readings on Cp will show the air capacitance of Cx. 3. Introduce the liquid dieleotrie under test between plates of Condenser Cx and balance Cx and Cp (in parallel) against Ca. Dis connect Cx and without changing Ca, obtain balanoe again by adjusting Cp. The difference in readings on Cp will show capaoitance of Cx with the liquid under test as dielectric. 4* Calculate dleleotrio constant by dividing eapaoitanoe of Cx using liquid dleleotrio by oap&oitanoe of Cx with air dleleotrio. 3* During the measurements, Condenser Cx is kept in a oonstant temperature oven to maintain temperature of dielectric at 100 C. 6. The resistance R is adjusted simultaneously with the variable condenser to obtain balance. The resistance readings are immaterial. ^eb. 2, 1932 1 i.L . .. . ; DSW 550960 ... i. STLCOPCB4089377