MEASURING FORCES AND WEAK IN S\\ ITCIIIXG Al'l'AKATLS 47*.) 



CONTACT MAKE 



Z 30 - 



/^i^yi^^Kw 



CONTACT BREAK 



2 3 4 5 



TIME IN MILLISECONDS 



Fig. 6 — Oscillograph tracings of forces generated in make and break opera- 

 tions. 



direction of the electrodes. In this process, the crystal is first poled, after 

 which the poling electrodes are ground or etched off and electrodes per- 

 pendicular to the poling direction are put on by using a polimerizing 

 cement in which silver dust is mixed. The cement serves not only as an 

 electrode but also holds the ceramic in the desired place. Fig. 7 shows 

 an arrangement used for studying frictional forces. A small ceramic 0.1 

 l)y 0.1 cm in cross-sectional area is glued to a metal base while a thin 

 specimen of the material whose frictional forces are to be studied is 

 glued to the top surface. The forces cavised by a wire drawn over the 

 surface are transmitted to the crystal and generate a voltage which ap- 

 pears on the oscillograph. Pictures of such force generated voltages are 



TANGENTIAL--' 

 BARIUM TITANATE 

 CERAMIC 



-SAMPLE 



Fig. 7 — Experimental arrangement for studj'ing frictional forces. 



