| 摘要 |
A coil (1) which produces the magnetic field encircles the user's arm or leg. A d.c. supply (3) is fed via an electronic switching bridge (5, 6, 7, 8) with flywheel diodes to the coil (1). The current fed to the coil is detected using a series resistance (15). The control circuit (13) switches the electronic switches (5, 6, 7, 8) to produce the required frequency, set using a potentiometer (14). The amplitude is controlled by another potentiometer (16) which reduces or increases the length of time for which the pulses are fed to the coil.
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