초록 ▼

A control circuit is disclosed suitable for use with a toaster or other food browning device which utilizes a radiant energy source to brown food. A light sensitive variable resistor, or photocell, is optically coupled to light reflected from the food being browned in the device. A voltage generated

A control circuit is disclosed suitable for use with a toaster or other food browning device which utilizes a radiant energy source to brown food. A light sensitive variable resistor, or photocell, is optically coupled to light reflected from the food being browned in the device. A voltage generated by a voltage divider including the light sensitive resistor therein is compared with a preselectable voltage generated by a second voltage divider to determine whether the heat source should be turned on or off. Suitable solid state control circuitry is provided to ensure that a start-up delay is provided at the beginning of each browning cycle and to reset the circuit for future operation when the desired browning of the food is achieved.

대표청구항 ▼

In a food browning device which utilizes a light generating heat source to brown food, the control circuit comprising: a switching device connected to control the operation of the heat source; a first resistive voltage divider including a variable resistor therein, the variable resistor being manual

In a food browning device which utilizes a light generating heat source to brown food, the control circuit comprising: a switching device connected to control the operation of the heat source; a first resistive voltage divider including a variable resistor therein, the variable resistor being manually variable; a second resistive voltage divider including a fixed resistor and a light sensitive variable resistor, the light sensitive variable resistor being optically coupled to light reflected from the food being browned; a voltage comparator connected to both the first and second voltage dividers and connected so as to de-energize the switching device to turn off the heat source when the voltage generated by the second voltage divider achieves a pre-selected relation relative to the voltage generated by the first voltage divider; a bistable circuit switchable between on and off states connected to the switching device so as to prevent operation of the switching device when the bistable circuit is in its off state, the switching of the bistable circuit to its on state initiating operation of the switching device; a timing circuit connected to the output of the voltage divider, the timing circuit creating a timing pulse, the timing circuit connected to the switching device so as to prevent operation of the switching device during the timing pulse and also connected to the bistable circuit to switch the bistable circuit to its off state at the end of the timing pulse; and a manually operable start-up switch connected to the bistable circuit so as to be capable of switching the bistable circuit from its off state to its on state to initiate operation of the switching device, the operation of the control circuit thereafter being unaffected by the operation of the start-up switch.