Abstract: An anti-theft security device and alarm for detection of the disconnection of electronic equipment such as video cassette recorders from a series electronic signal path loop is disclosed. The chassis of the VCR or other electronic audio-visual equipment is used to complete a series connection between a security circuit and a ground potential signal so that disconnection of the electronic equipment on diplay from the sucurity circuit will cause an open circuit condition. The open circuit condition is detected by an alarm circuit, and the alarm circuit responds by producing an alarm signal which is supplied to audio and visual signalling devices to produce audible and visible theft alert signals.