| 摘要 |
PURPOSE:To hold a current, which is supplied to an input-side LED, in an approximately constant value for many kinds of input signal voltage different in voltage value, by connecting a constant current circuit in series to the input- side LED of a photocoupler provided in a signal input circuit. CONSTITUTION:When a DC input signal voltage is applied across terminals 1-1 and 1-2, a constant current circuit 5 supplies an approximately constant current to an input-side LED 3-1 of a photocoupler 3 for many kinds of input voltage different in voltage value, for example, 24V, 48V, and 100V. Thus, a signal supplied to an internal operating circuit from terminals 4-1 and 4-2 of an output- side transistor 3-2 is set to an approximately constant level in accordance with the input signal. |
