Temperature regulating circuit for soldering iron

Abstract

Abstract PURPOSE:To detect the temp. of a heater without using a temp. sensor and to execute temp. regulation by detecting the exothermic temp. of the heater from the change in the DC resistance of the heater and executing the temp. regulation. CONSTITUTION:It is assumed that voltage drop quantity is detected in a resistance value detecting circuit 7 and that the voltage drop quantity is larger than the potential set in a variable resistor 9 as a result of the comparison made with said voltage drop quantity and the potential set in the resistor 9 in a voltage comparator circuit 8. A '0' is outputted from the circuit 8, is latched by a latch circuit 10 and is supplied to an OR gate 4. AC current I is no more supplied to the heater 1 and the temp. of the heater 1 begins to fall as a result of natural cooling. A signal S1 rises next. A '1' is outputted from the circuit 8 when the heater 1 cools and the temp. thereof falls to the set temp. or below in this stage. The AC current I is again supplied to the heater 1 when the signal S1 falls. The temp. of the heater rises accordingly. The temp. of the heater 1 is thus maintained at the set temp.

Inventors

• 👤 Shigeki Kuwano
• 👤 桑野　茂樹
• 👤 Koji Minowa
• 👤 箕輪　光司

Bibliographic Details