Low voltage lamp switcher circuit
First Claim
1. A power switching circuit means for alternately switching off and on second lamp means in a group of first and second lamp means as the group of lamp means is repeatedly switched on, so that upon each alternate switching on of the group of lamp means the second lamp means remain switched off, comprising:
- first and second terminals for connecting to a power source controlled by a main switch,first lamp means connected to the terminals for providing illumination on every occasion when the main switch provides power to the terminals from the power source,third terminal means,switching means connected to said first and third terminals for alternatively connecting and disconnecting said third terminal from said first terminal,second lamp means connected to said third and second terminals for providing illumination on each alternate occasion when the main switch provides power to the terminals from the power source,power conversion means connected to said first and second terminals for converting power from the power source to a regulated direct current output,control circuit means connected to the direct current output of said power conversion means for operating said switching means, comprising means for detection of disconnection of power from said first and second terminals, operating means for switching said switching means for a first condition to a second condition and from the second condition to the first condition and means for determining which of said first and second conditions said switching means is in while power is applied to said first and second terminals, wherein the said power conversion means comprises a bridge rectifier means having two input terminals and a positive and a negative output terminal, a first capacitor connected in series with one of said input terminals and in series with a first resistor to said second terminal, the other of said input terminals being connected to said first terminal, a first diode means whose cathode is connected to said negative output terminal, a Zener diode whose cathode is connected to said positive output terminal and whose anode is connected to the anode of said first diode means, and across which an essentially constant direct voltage is developed for supplying said control circuit means, said first resistor being provided to limit the maximum surge current into said first capacitor to a safe value.
2 Assignments
0 Petitions
Accused Products
Abstract
An improved lamp switching circuit for switching on a second lamp circuit upon every alternate application of power to a first lamp circuit. A magnetic latching relay alternately connects and disconnects the second lamp circuit in parallel with the first whenever power to the circuit is switched off. The relay is powered by the discharge of one of two capacitors, which respectively operate a set circuit and a reset circuit of the latching relay. Only one of the capacitors is charged at any time. While power is applied to the lamp circuits, one capacitor is charged while the other is kept discharged, in preparation for operation of the latching relay. When power is switched off, a control circuit senses this condition and triggers a thyristor to discharge the capacitor through the corresponding relay coil after a short predetermined time delay. A low voltage regulated power supply is derived from the a.c. power to provide the power needed by the control circuit and to charge the capacitors, making the circuit operation reliable over a wide range of supply voltages and temperatures.
15 Citations
11 Claims
-
1. A power switching circuit means for alternately switching off and on second lamp means in a group of first and second lamp means as the group of lamp means is repeatedly switched on, so that upon each alternate switching on of the group of lamp means the second lamp means remain switched off, comprising:
-
first and second terminals for connecting to a power source controlled by a main switch, first lamp means connected to the terminals for providing illumination on every occasion when the main switch provides power to the terminals from the power source, third terminal means, switching means connected to said first and third terminals for alternatively connecting and disconnecting said third terminal from said first terminal, second lamp means connected to said third and second terminals for providing illumination on each alternate occasion when the main switch provides power to the terminals from the power source, power conversion means connected to said first and second terminals for converting power from the power source to a regulated direct current output, control circuit means connected to the direct current output of said power conversion means for operating said switching means, comprising means for detection of disconnection of power from said first and second terminals, operating means for switching said switching means for a first condition to a second condition and from the second condition to the first condition and means for determining which of said first and second conditions said switching means is in while power is applied to said first and second terminals, wherein the said power conversion means comprises a bridge rectifier means having two input terminals and a positive and a negative output terminal, a first capacitor connected in series with one of said input terminals and in series with a first resistor to said second terminal, the other of said input terminals being connected to said first terminal, a first diode means whose cathode is connected to said negative output terminal, a Zener diode whose cathode is connected to said positive output terminal and whose anode is connected to the anode of said first diode means, and across which an essentially constant direct voltage is developed for supplying said control circuit means, said first resistor being provided to limit the maximum surge current into said first capacitor to a safe value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
Specification