The photographs show you one of the strip chart recorders that will be used in the Dental Materials Workshop. The close-ups show the controls.

Many measuring instruments, as for instance Wilson's reometer output a varying electrical voltage. When a process is to be monitored in time, a strip chart recorder can be used. The strip chart recorder translates the voltage to the position (left to right) of the tracing pen, which draws a line on the strip of paper, which is transported through the recorder with a constant speed. In this way the measured voltage is plotted versus time. 

The input sensitivity switches (1) and (2) are used to set the voltage required to move the pen from the left to the right. Please note that 1 V = 1000 mV. With switch (3) in position 'CAL' this will be the exact value marked at switches (1) and (2) and in position 'VAR' the sensitivity may be adjusted with (4). With twisting knob (5) and switch (6) the pen can be moved left or right, independent of the input voltage. Because there are two pens and two inputs, these elements (1..6) occur twice.

Two gears (8) transport the paper through the recorder, underneath the ruler (7).

Slider (9) lifts the pen. The speed of the paper is set with dial (10). The paper will start running when switch (11) is put in the correct position. This switch has three positions: forward, stop, and backward. 
Switch (12) has the same three positions, but it will spring back to the middle (=stop) position. This switch is used to put the paper in the correct position. When it is operated, the paper starts moving slowly, but after a few seconds it will move quicker.
Switch (13) is the power on/off switch.