Original Publication Date: 1961-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Cronkhite, MH: AUTHOR [+2]
AbstractThis ratiometer determines the ratio of the in-phase component of an unknown voltage with respect to a known voltage.
This ratiometer determines the ratio of the in-phase component of an unknown voltage with respect to a known voltage.
In the left-hand drawing, CA represents the known voltage Vk and CD the unknown voltage Vx. Point E is established by a voltage divider such that CE = ED. Then, if EB is made equal to CE or ED, CB represents the in-phase component of the unknown voltage Vx.
In the circuit, Vk is impressed across calibrated autotransformer 10. Vx is applied to a precision voltage divider comprising resistors 11 and 12. When switch 13 engages contact 14, the voltage across resistor 11 or ED is applied to diode bridge 15. D.C. null indicator 16 is zeroed by adjusting the movable pointer of potentiometer 17. Switch 13 is now moved to contact 18 to apply the voltage EB across 15. The movable dial 19 of 10 is adjusted until 16 again reads zero. The ratio VI/Vk is read directly from dial 19 of 10. The feedback amplifier 20 provides increased input impedance and noise rejection.