Delayed turn-on solid state relay

Claim 2

A solid state relay comprising: first and second silicon-controlled rectifiers connected in back-to-back parallel, oppositely poled relationship; said second silicon-controlled rectifier connected across said first silicon-controlled rectifier so as to be operated thereby; means for providing a gate voltage to turn ON said first silicon-controlled rectifier in response to a control signal; means responsive to the voltage drop across said first siliconcontrolled rectifier for controlling a conduction cycle of said second silicon-controlled rectifier; said conduction cycle being defined as the initiation of operation of said second silicon-controlled rectifier at a delayed time; and means for connecting said first and second silicon-controlled rectifiers in series with a load and an AC power source.

Claim 3

A relay as defined in claim 1 wherein said last-mentioned controlling means comprises: a first capacitor charged by said voltage drop; and means cooperating with said first capacitor to control the gate voltage of said silicon-controlled rectifier in response to the charge on said first capacitor.

Claim 4

A slave circuit for controlling the conduction cycle of a second silicon-controlled rectifier in response to the voltage drop across a first silicon-controlled rectifier, said first and second silicon-controlled rectifiers being reversely parallel-connected, said circuit comprising: a first capacitor, a first resistor and a first diode connected in series across the anode and cathode of said second rectifier; a second diode, the cathode of which is connected to the junction of said first resistor and said first diode; a second resistor and a second capacitor connected in parallel between the anode of said second diode and the anode of said second rectifier; a third resistor and a third diode connected in series between the junction of said second diode and said second resistor and said second capacitor and the cathode of said second rectifier; and the gate of said second rectifier being connected to the junction of said third resistor and said third diode.

Claim 5

A slave circuit for controlling the conduction cycle of a second silicon-controlled rectifier in response to the voltage drop across a first silicon-controlled rectifier, said first and second silicon-controlled rectifiers being reversely parallel-connected, said circuit comprising: a first capacitor, a first resistor and a first diode connected in series across the anode and cathode of said second rectifier; a second diode, the cathode of which is connected to the junction of said first resistor and said first diode; a second resistor and a second capacitor connected in parallel between the anode of said second diode and the anode of said second rectifier; a third resistor and a third diode connected in series between the junction of said second diode and said second resistor and said second capacitor and the cathode of said second rectifier; and the gate of said second rectifier being connected to the junction of said third resistor and said third diode.

Claim 6

The invention as defined in claim 2 including a neon indicating lamp and a series dropping resistor connected directly across said rectifiers and being adapted to visually indicate when said rectifiers are not operating properly.

Claim 7

A solid state relay for applying an AC current at a gradual rate to the filament of an incandescent lamp comprising: a silicon-controlled rectifier characterized by its ability to conduct in both directions upon the application of either polarity of a gate signal; and a thermistor directly coupled to said rectifier for activation thereof as a function of the applied AC voltage.

Claim 8

A solid state relay for applying an AC current at a gradual rate to the filament of an incandescent lamp comprising: a silicon-controlled rectifier characterized by its ability to conduct in both directions upon the application of either polarity of a gate signal; and a thermistor directly coupled to said rectifier for activation thereof as a function of the applied AC voltage.

Claim 9

The invention as defined in claim 5 including a neon indicating lamp and a series dropping resistor connected directly across said rectifier adapted to indicate when the relay is not operating properly.

Claim 10

A solid state relay for applying an AC current at a gradual rate to the filament of an incandescent lamp comprising: a silicon-controlled rectifier characterized by its ability to conduct in both directions upon the application of either polarity of a gate signal; a thermistor characterized to operate as a function of the applied AC voltage thereto; a capacitor coupled to said thermistor and being chargeable in response to operation of said thermistor to develop a breakover voltage; and a diode directly coupled bEtween said thermistor and said rectifier operable in response to the developed breakover voltage to apply the stored charge in said capacitor at said gate signal to activate said rectifier.

Claim 11

A solid state relay for applying an AC current at a gradual rate to the filament of an incandescent lamp comprising: a silicon-controlled rectifier characterized by its ability to conduct in both directions upon the application of either polarity of a gate signal; a thermistor characterized to operate as a function of the applied AC voltage thereto; a capacitor coupled to said thermistor and being chargeable in response to operation of said thermistor to develop a breakover voltage; and a diode directly coupled bEtween said thermistor and said rectifier operable in response to the developed breakover voltage to apply the stored charge in said capacitor at said gate signal to activate said rectifier.

Claim 12

In a solid state relay of the type utilizing first and second parallel-connected, reversely poled silicon-controlled rectifiers, the improvement comprising: means responsive to a voltage drop across said first silicon-controlled rectifier, for controlling the conduction cycle of said second silicon-controlled rectifier; a first capacitor charged by said voltage drop; means cooperating with said first capacitor to control a gate voltage of said second silicon-controlled rectifier in response to the charge on said first capacitor; a second capacitor; and means for charging said second capacitor to a reference voltage responsive to the charge in said first capacitor, and wherein said voltage is proportional to the algebraic sum of said reference voltage and the voltage at the anode of said silicon-controlled rectifier.

Claim 13

In a solid state relay of the type utilizing first and second parallel-connected, reversely poled silicon-controlled rectifiers, the improvement comprising: means responsive to a voltage drop across said first silicon-controlled rectifier, for controlling the conduction cycle of said second silicon-controlled rectifier; a first capacitor charged by said voltage drop; means cooperating with said first capacitor to control a gate voltage of said second silicon-controlled rectifier in response to the charge on said first capacitor; a second capacitor; and means for charging said second capacitor to a reference voltage responsive to the charge in said first capacitor, and wherein said voltage is proportional to the algebraic sum of said reference voltage and the voltage at the anode of said silicon-controlled rectifier.

Claim 14

In a solid state relay of the type utilizing a first and a second parallel-connected, reversely poled silicon-controlled rectifiers, the improvement which comprises: said second silicon-controlled rectifier electrically connected across said first silicon-controlled rectifier; circuit means responsive to the absence of a voltage drop across said first silicon-controlled rectifier and operable for controlling conduction of said second silicon-controlled rectifier; said conduction being defined as the initiation of operation of said second silicon-controlled rectifier at a delayed time; means for connecting said first silicon-controlled rectifier and said second silicon-controlled rectifier in series with a load and an AC power source; and wherein said delayed time is defined as meaning conduction of said first silicon-controlled rectifier within a first AC cycle while conduction of said second silicon-controlled rectifier occurs several AC cycles later.

Claim 15

In a solid state relay of the type utilizing a first and a second parallel-connected, reversely poled silicon-controlled rectifiers, the improvement which comprises: said second silicon-controlled rectifier electrically connected across said first silicon-controlled rectifier; circuit means responsive to the absence of a voltage drop across said first silicon-controlled rectifier and operable for controlling conduction of said second silicon-controlled rectifier; said conduction being defined as the initiation of operation of said second silicon-controlled rectifier at a delayed time; means for connecting said first silicon-controlled rectifier and said second silicon-controlled rectifier in series with a load and an AC power source; and wherein said delayed time is defined as meaning conduction of said first silicon-controlled rectifier within a first AC cycle while conduction of said second silicon-controlled rectifier occurs several AC cycles later.

Claim 16

A relay as defined in claim 9 wherein said means for controlling comprises: a first capacitor charged by said voltage drop; and means cooperating with said first capacitor to control a gate voltage of said second silicon-controlled rectifier in response to the charge on said first capacitor.