US 4,733,103 A · Light sensitive switching circuit

Abstract

A light sensitive switching circuit for automatically controlling the supply of electric power from a power source to a load, such as a lantern, is disclosed. When it becomes darker than a predetermined brightness the power supply starts and when it becomes bright again, the power supply is cut. The light sensitive switching circuit comprises first and second lines for connecting the power source and the load in series between the first and second lines. A first thyristor is connected between the first and second lines, and a second thyristor connected is to the first thyristor such that the anode of the second thyristor is connected to the gate of the first thyristor and the cathode of the second thyristor is connected to the cathode of the first thyristor. A photocell is connected between the gate and the cathode of the second thyristor.

Claims16

Dependent claims

A light sensitive switching circuit for supplying electric power from a power source to a load when it becomes darker than a predetermined brightness comprising:

first and second lines means for connecting said power source and said load in series therebetween to supply power from said power source;
a first thyristor connected between said first and second lines means;
a second thyristor connected to said first thyristor such that the anode of said second thyristor is connected to the gate of said first thyristor and the cathode of said second thyristor is connected to the cathode of said first thyristor;
a photovoltaic cell connected between the gate and the cathode of said second thyristor.

1 more element

A light sensitive switching circuit for supplying electric power from an AC power source to a load when it becomes darker than a first predetermined brightness and cutting the power when it becomes brighter than a second predetermined brightness, which is brighter than said first predetermined brightness, comprising:

first and second lines means for connecting said power source and said load in series therebetween;
a first thyristor connected between said first and second lines means;
a second thyristor connected to said first thyristor such that the anode of said second thyristor is connected to the gate of said first thyristor and the cathode of said second thyristor is connected to the cathode of said first thyristor;
a first photocell means connected between the gate and the anode of said second thyristor;
a third thyristor connected to said first thyristor such that the anode of said third thyristor is connected to the gate of said first thyristor;
a second photocell means connected between the gate and the anode of said third thyristor, said second photocell means being sensitive to a brighter light than that sensitive to said first photocell means;
a bypass circuit connected across said first thyristor for producing a predetermined voltage when said first thyristor is off;
and
a transistor connected between the cathode of said first thyristor and the cathode said third thyristor and controlled by said bypass circuit such that said transistor turns on when said predetermined voltage is produced by said bypass circuit.

6 more elements

first and second lines means for connecting said power source and said load in series therebetween;
a first thyristor connected between said first and second lines means;
a second thyristor connected to said first thyristor such that the anode of said second thyristor is connected to the anode of said first thyristor and the cathode of said second thyristor is connected to the gate of said first thyristor;
a third thyristor connected to said second thyristor such that the anode of said third thyristor is connected to the gate of said second thyristor and the cathode of said third thyristor is connected to the cathode of said second thyristor;
a first photocell means connected between the gate and the anode of said third thyristor;
a fourth thyristor connected to said first thyristor such that the anode of said fourth thyristor is connected to the anode of said first thyristor and the cathode of said fourth thyristor is connected to the gate of said first thyristor;
a fifth thyristor connected to said fourth thyristor such that the anode of said fifth thyristor is connected to the gate of said fourth thyristor and the cathode of said fifth thyristor is connected to the cathode of said fourth thyristor;
a second photocell means connected between the gate and the anode of said fifth thyristor, said second photocell means being sensitive to a brighter light than that sensitive to said first photocell means;
a bypass circuit connected across said first thyristor for producing a predetermined voltage when said first thyristor is off;
and
a transistor connected between the cathode and the anode of said third thyristor and controlled by said bypass circuit such that said transistor turns on when said predetermined voltage is produced by said bypass circuit.

8 more elements

Dependencies are inferred from the claim text.

Light sensitive switching circuit

Life of this patent

Light sensitive switching circuit

Life of this patent

Abstract

Claims16