Abstract An electrical circuit for automatically adapting an inductive load to that of one of two possible A.C. supply voltages applied across the circuit. The circuit comprises a capacitor connected in series with the load. The capacitor value is such that a series resonant circuit is formed with the load at a frequency of operation. A controlled semiconductor device having a pair of terminals and a gate terminal is connected with the pair of terminals in parallel across the capacitor. The gate terminal is connected through a non-linear current-voltage characteristic electrical component to one of the terminals of the A.C. supply voltage. For the lower A.C. supply voltage, the capacitor and inductor form a series resonant circuit and at the higher A.C. supply voltage, the controlled semiconductor device short circuits the capacitor.
An electrical circuit for automatically adapting an inductive load to one of two possible A.C. supply voltages comprising: a capacitor connected in series with said load, said capacitor value being such that a series resonant circuit formed with the inductive load is at resonance at the lower A.C. voltage, a controlled semiconductor device having a pair of terminals connected across said capacitor, and a gate terminal, the gate terminal of said semiconductor device being connected through an electrical component having a non-linear current-voltage characteristic to one side of the A.C. voltage supply, wherein said controlled semiconductor device is utilized to short circuit said capacitor at said higher of said two possible A.C. voltages.
Claim 2
Dependent Claim
113 words
An electrical circuit for automatically adapting an inductive load to one of two possible A.C. supply voltages comprising: a capacitor connected in series with said load, said capacitor value being such that a series resonant circuit formed with the inductive load is at resonance at the lower A.C. voltage, a controlled semiconductor device having a pair of terminals connected across said capacitor, and a gate terminal, the gate terminal of said semiconductor device being connected through an electrical component having a non-linear current-voltage characteristic to one side of the A.C. voltage supply, wherein said controlled semiconductor device is utilized to short circuit said capacitor at said higher of said two possible A.C. voltages.
Claim 3
Dependent Claim
20 words
An electrical circuit in accordance with claim 1 wherein said component having a non-linear current-voltage characteristic is a voltage-dependent resistor.
Claim 4
Dependent Claim
23 words
An electrical circuit in accordance with claim 1 wherein said component having a non-linear current-voltage characteristic comprises a pair of series-opposed Zener diodes.
Claim 5
Dependent Claim
20 words
An electrical circuit in accordance with claim 1 wherein said component having a non-linear current-voltage characteristic comprises a glow lamp.
Claim 6
Dependent Claim
18 words
An electrical circuit in accordance with claim 1 wherein said controlled semiconductor device is a bi-directional semiconductor switch.