Rez-n-bond limit the angle of rotation of the disk so that 
the fragile connecting wires to the slidewire will not 
break if the clamp comes loose from the plant. The two 
~ stops are positioned so that they strike the shelf top as 
the contact reaches each end of the slidewire (fig. 6). 
Electrical Circuit 
Figure 7 shows schematic diagrams and a parts list of 
the voltage regulator and sensor. 
It is convenient to operate three sensors from each 
voltage regulator. The voltage regulator is built into a 
small Minibox. The Minibox is wrapped in sheet plastic 
to protect it from the weather and is mounted on a 
tripod leg with a laboratory clamp. The voltage regulator 
is connected to a laboratory power supply! ° with 
lightweight extension cord wire. The power supply, 
housed in the recorder shelter, furnishes a well-filtered 
10 volts d.c. to the voltage regulator. Lightweight 
up Electro D-6127 T Power Supply manufactured by Electro 
Products Laboratories, Chicago, III. 
R3— 
(SLIDEWIRE) 
extension cord also is used to connect voltage regulator 
and sensors. 
A single voltage regulator (resistance values shown in 
figure 7) is used with three sensors, each having a 
slidewire resistance of 5 ohms. The apparatus shown in 
figure 7 was designed for use with a recorder having a 
span of 0-9 mv.'! Shielded cable should be used for 
signal leads from the sensors to the recorder. 
The voltage regulator provides a constant voltage 
across the sensor slidewires independent of fluctuations 
in temperature and line voltage. A 5.6-v. Zener diode is 
used in the voltage regulator. The circuit is designed to 
operate the Zener diode with a reverse current of 50 
ma., the condition under which its operation is least 
1l The recording potentiometer used was a Honeywell 
Electronik 15 model with a nominal range of 0-10 mv. This 
recorder is equipped with an accessory event-marking pen that 
was connected to an anemometer to obtain a wind trace along 
the upper margin of the chart. Use of the marking pen limited 
the useful range of the recording potentiometer to 0-9 mv. 
Figure 6.—The contact is shown at the end of its travel over the slidewire, R3, with the stop against the right-hand side of the 
shelf. Resistor Rs is visible at the back of the shelf together with its ‘’flea clip’’ mountings. The clamp wire (1) and weight 
cord (2) are in place wound in opposite directions around the axle. The millivolt dial-marks can be seen along the rim of the 
disk. 
