RUSH CURRENT PREVENTIVE CIRCUIT AND POWER SUPPLY FOR MICROWAVE OVEN

Japanese Patent JPH1118288

A

PROBLEM TO BE SOLVED: To provide a circuit for preventing rush currents which are produced when alternating-current power is supplied intermittently to a load, and its application to a microwave oven. SOLUTION: A PTC(positive characteristic) thermistor 12, which limits the magnitude of current output to a load to a specified value or below due to its temperature- resistance characteristic even if a rush current exceeding the specified value is applied, is placed between a power supply and a load and is connected with a switch 10 in parallel. After a specified delay time has passed from the time at which an alternating- current signal is input to a full-wave rectifier, a direct-current relay 14 is excited by a direct-current signal from the full-wave rectifier and provides a switch 10 with a signal to turn on the switch. The switch turned on is provided to the bypass circuit of the PTC thermistor 12. During the period of the specified delay time from the time of input of an alternating-current signal to the full-wave rectifier, the alternating- signal is supplied to the load through the PTC thermistor 12. After the delay time has passed, the alternating-current signal is supplied to the load through the switch. Thus rush currents which are produced during intermittent power supply are interrupted effectively.

KIM YOU HO

JP32820397A

January 22, 1999

November 28, 1997

Click for automatic bibliography generation  

DAEWOO ELECTRON CO LTD

H05B6/68; G05F1/10; H01C7/02; H01C7/13; H02H9/00; H02H9/02; H02M7/06; H02M7/12; H05B6/66; (IPC1-7): H02H9/02; G05F1/10; H01C7/02; H01C7/13; H02M7/06

Previous Patent: HIGH-VOLTAGE TRANSMISSION LINE SWITCHING DEVICE

Next Patent: CONTROL CIRCUIT FOR SEMICONDUCTOR DEVICE