| 摘要 |
PURPOSE:To vary a duty ratio and a flicker period independently of each other with a simple constitution, by comparing the charging voltage of the capacitor of a relaxation oscillating circuit with a reference voltage and by controlling a switch part by the comparison output. CONSTITUTION:A relaxation oscillating circuitIis operated by a voltage obtained by rectifying an AC power source E by diodes D1-D4. When a charging voltage VA of a capacitor C2 of the circuitIbecomes higher than a reference voltage Vd determined by resistances R5-R7 of a comparing part II, a comparator 2 is turned off to make a thyristor TH3 of a switch part III conductive. When the voltage VA reaches a gate voltage VG of a PUT1, the PUT1 becomes conductive, and charge of the C2 is discharged, and the comparator 2 is turned on to cut off the TH3. By repeating this operation, power is supplied intermittently to a relay RY of a relay part - to flicker a light emitting diode LED. The value of a resistance R8 is changed to change the flicker period with a constant duty ratio, and the value of the resistance R5 or R6 is changed to change the duty ratio with a constant flicker period. |
