Dual isolated between channels
There are tow output jacks on the right side of the device.
The electrode jack provides the current for the treatment. It accepts the right angle sub-miniature plug which is connected to the electrode.When the frequency is 6HZ, the LEDS flash on for about 1/12 second and then off for about 1/12 second. At 10 cycles per second the flashing is much faster.
That speed is still visible to the eye and is obviously flashing. At the HIGH FREQUENCY settings of 30 and 300 Hz, the light is flashing very fast and appears to be a solid light because it is flashing too fast for the eye to discriminate the flashes.