| 摘要 |
PROBLEM TO BE SOLVED: To provide a phase control type solid state relay eliminating the need of a large-sized component such as a transformer though it is a phase control type, making two input terminals and two output terminals sufficient for external terminals and hardly receiving the influence of noise or the like from the outside. SOLUTION: A reference resistor R0 connected to a positive input terminal 1 and a Zener diode ZD0 connected to a negative input terminal 1' are serially connected and the both-terminal voltage of the Zener diode ZD0 is used for the operation power source of a trigger pulse generation circuit composed of a CR charging circuit and comparators CMP1 and 2. Also, a main thyristor TAC and a zero voltage detection circuit ZV are parallelly connected to output terminals 2, 2', the signals of the zero voltage detection circuit are electrically insulated in a photocoupler PC1 and transmitted to an input side circuit and the charging and discharging of the charging capacitor of the CR charging circuit are controlled. The charging/discharging voltage and a voltage generated at both terminals of the reference resistor are compared in the comparator of the trigger pulse generation circuit and trigger pulses are generated. The trigger pulses are electrically insulated in a photo thyristor coupler PC2 and transmitted to the gate of the main thyristor on an output side and the main thyristor is controlled. |
