Circuit #6000-A & Rustrak 288
( 12-17-1991 )
Note: Above responses were confirmed with Hooke’s scale gravimeters!
I. Circuit # 6000-A
a. TLC 271 used with +9V supply
b. AC operation achieved with non-inverting input connected to 200K pot connected across +9V supply (off-set control).
c. Input jack provided for use with external 12V DC supply.
d. Cin (detector) ~ 2200 uF (10V).
e. Internal LP filter ~ 5 Hz.
f. RF ~ 2.5 M.
g. The output of Ckt. # 6000-A is thus highly filtered and will not show much fine structure, but a highly averaged value for the Earth’s g-field.
h. 3-diode off-set used also.
II. Rustrak 288
a. 1 mA at 100 Ohms made into 0-1 V meter with 1 Kohm series resistor.
b. Chart range ~ 0 to 1000 mV.
c. Ckt. # 6000-A adjusted with RF and off-set controls to read 650 mV on Rustrak chart. This was roughly equivalent to 32 ft/sec2 for the value of the g-field!
d. The test run shown above was made with an external AC line-powered DC supply of 12 V to avoid any response ‘droop’ due to a weakening battery suppl.
a. The test run showed the highest value of averaged g-field around the hours of 4-5 and minimum values of g-field around the hours of 10-11.
b. The response is similar to the cosine (sine) function seen in tests in the past.
c. Using an average value of 625 mV and excursions of +/- 25 mV, the resulting variation is about +/- 4% !!
d. The g-field maximums still appear to be related to the Leo Regions?