Off-delay timing apparatus

Claim 1

In an apparatus for energizing a load from sources of A.C. or D.C. voltage supply, and having an OFF time delay deenergizing mode upon re-opening of a control switch, the combination comprising: a. a selectively operable switch for connection to a voltage supply source b. a unidirectional conducting device in circuit with said switch and connectable to a load for supplying the same whenever said switch is closed with D.C. current or half waves of A.C. current of one polarity according to the type of current provided by the voltage supply source c. semiconductor means for connection to the voltage supply source and the load and having control means energizable to provide the same current conduction modes to the load as said unidirectional conducting device d. second semiconductor means for connection to the voltage supply source and having control means energizable to provide half waves of A.C. current flow of opposite polarity when the source of voltage is A.C. e. means including a electromagnetic switch having a control winding which when energized effects closure of contacts to render the first mentioned semiconductor means effective when said supply voltage is D.C. and both of said semiconductor means effective when the supply voltage is A.C. f. means which when connected to an A.C. and D.C. supply source affords a source of unidirectional potential g. means for energizing the control winding of said electromagnetic switch upon closure oF said selectively operable switch and for deenergizing said control winding after a time delay period upon reopening of the latter switch comprising: h. transistor means in circuit with said source of unidirectional potential and said control winding and being controllable to energize and deenergize said control winding i. control means for said transistor means in circuit with said selectively operable switch and said source of unidirectional potential comprising: j. time delay means including capacitor means quickly chargable to a given level upon closure of said selectively operable switch to render said transistor means operable to correspondingly energize said control winding and further including an adjustable resistance discharge path which is rendered effective upon reopening of said selectively operable switch to discharge said capacitor means during a time delay period to another level which causes said transistor means to deenergize said control winding.