Universal square-wave sound generator with approx. 1000 Hz basic frequency and a great number of harmonic waves which lead up to VHF-range. The signal can be listened through a highly ohmic earphone or could be amplified for loudspeakers through an amplifier. Ideal as repair equipment for radios and amplifiers, in order to feed a sound signal at various stages of the defect object. Operating voltage 6 - 12 V/DC Frequency approx. 1000 Hz Board dimensions approx. 25 x 24 mm