| 摘要 |
PURPOSE:To enable displaying of a maximum temperature, by a method wherein a reference resistance, constituting a time constant circuit of an oscillator, is switched into a temperature resistance, an oscillating frequency thereof is compared, a temperature value corresponding to an output thereof is latched, and when it exceeds a value latched before, a latch content is renewed. CONSTITUTION:With a FF1 reset and set, a thermister Rx and a reference resistance R are selected. A counter 2 counts an oscillating frequency in which a reference resistance R and a capacitor C form a time constant, and is inputted to a latch circuit 3. Its overflow signal clears counters 2 and 6 through a delay circuit 4, and simultaneously, inverses the FF1. The oscillating frequency, in which the Rx and C form the time constant, is counted by the counter 2, and its output signal is compared with the content of the latch circuit 3 by a comparing circuit 16. If the output signal exceeds the content, the latched content of the latch circuit 3 is renewed via a numerical control circuit 17 by means of a strobe signal of a NOR circuit 20, and a maximum temperature conversion data is normally held to display it in a display unit 31. |
