An electrical stimulator can be useful in aiding understanding of the muscles in the human body. Such life-saving devices as the automatic electronic defibrillator (AED) operate on the principle of sending electronic impulses through a muscle--in this case, the human heart--to initiate movement. On a smaller, less grand scale, for science fair projects or hobbies, a simple electric stimulator can be constructed from speaker wire and a few other components readily available at a local hardware or electronics supply store.
Split both ends of the speaker wire about 2 inches down each end so you have four separate ends.
Strip approximately a half-inch of insulation from all four ends.
Cut any connectors off the test probe leads.
Strip a half-inch of insulation from the wires of the test probe leads.
Strip a half-inch of insulation from the ends of the snap connector wires.
Twist together the exposed ends of the test probe leads and the exposed ends of the speaker wires on one end and secure with electrical tape.
Twist together the exposed ends of the snap connector wires and the exposed ends of the speaker wires on the other end and secure with electrical tape.
Snap a 9-volt battery into the snap connector and test the stimulator by touching the ends of the probes together. You should see a small spark. If you do not see a spark, check all connections and retest the stimulator.
This stimulator is an inexpensive device for demonstrating the effect of electrical stimulation on the leg muscles of dissected frogs in high school biology classes.