| 摘要 |
<p>PURPOSE:To prevent the electric conduction only in a negative cycle and to simplify the constitution of a temperature controller by generating a temperature setting signal only to a positive zero cross when a temperature setting signal and a temperature signal are in the non-inverted state. CONSTITUTION:An electric power control element 8 is serially connected to the AC power source 1 of the temperature controller through a heater 9, and a temperature detecting circuit 2 outputs the temperature signal including a ripple in accordance with the output of a temperature sensor 3. A temperature setting circuit 2 outputs a pulse-like temperature setting signal to the zero cross of the power source 1, and a comparator circuit 6 compares the temperature signal of the circuit 2 with the temperature setting signal of the circuit 4. An output circuit 7 executes the de-energized attitude of the element 9 in correspondence to the output of the circuit 6. A clock circuit 10 decides the generating time of the temperature setting signal of the circuit 4, and a memory circuit 11 stores the presence or absence of the output signal of the circuit 6. Then the circuit 10 generates always the output at a positive zero cross position and outputs the signal to a negative zero cross subsequent to the outputting of the circuit 11.</p> |
