This AC spark recording timer is used to measure velocity and acceleration of falling or moving objects in dynamics studies. It produces sparks at uniform time intervals which are marked on a paper tape. The distance between the marks is used to calculate velocity and acceleration. It comes with 120' of recording paper tape, 5 carbon discs, a table clamp, and a 300g weight. Uses standard AC 110-volt power. Includes a study guide with instructions and experiments.
The frequency is every 1/60th or 0.0167 seconds and is not adjustable. It features an on/off button. The red and black terminals can be used to attach optional items such as an oscilloscope (not currently available through Home Science Tools). It can be used with a low-friction rolling cart for speed and acceleration experiments.
The unit is 60hz (50hz is seen in the older photo).