Abstract: A circuit testing device comprises(a) a casing,(b) a single probe rigidly projecting from the casing whereby the casing may be manipulated to forcibly insert the probe into an electrical power socket, and(c) a presence-of-voltage circuit in the casing and electrically connected with the probe, said circuit including a presence-of-voltage indicator, and rectifier means and amplifier means electrically connected between the probe and the indicator.The device may also advantageously include a voltage level testing circuit, and an electrical continuity testing circuit.

Abstract: A circuit testing device includes a casing, two probes one of which projects from the casing, a voltage level testing circuit operatively connected with one probe and incorporating simple and advantageous circuitry including transistor amplifier means and indicator means, and an electrical continuity testing circuit connected between both the probes.

Abstract: A circuit testing device comprisesA. multiple probes at least one of which is sized for insertion into a single electrical socket receptacle to test for the presence of voltage, and two of which are applicable to spaced conductive elements to test for electrical continuity therebetween externally of said device,B. detection means operatively connected with said probes and including indicator means to indicate the presence or absence of voltage when said one probe is inserted into said socket single receptacle, and to indicate the presence or absence of electrical continuity when said two probes are applied to said spaced conductive elements.