This document discusses several types of low-frequency electrical stimulation techniques including diadynamic currents, high voltage pulsed galvanic stimulation, microcurrent, and Trabert current. It provides details on the waveform characteristics, physiological effects, indications, contraindications and application parameters for each technique. Diadynamic currents have five classic types that use rectified alternating current to produce monophasic pulses. High voltage galvanic stimulation uses twin peak monophasic pulses of short duration and low duty cycle. Microcurrent uses even lower intensities in the microampere range to stimulate tissue healing. Trabert current is a direct current with a 2 ms pulse and 5 ms interval, producing a frequency of around 143 Hz.