this is a square wave tone generator that puts out a really loud signal. it has a volume control, coarse pitch knob, and a fine pitch control that is switchable between a potentiometer and a light-dependent resistor. a quarter inch output jack and on/off switch are on the side of the die-cast aluminum box. the unit is powered by a 9v battery (not included…sorry).
(sound was also recorded by the digital camera, so it is extremely compressed…volume control doesn’t seem to do much in the video and much of the bass was cut)