Thyristor Semiconductor Products Page 30 Thyristor

2014 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 12/14/14 Teccor brand Thyristors AN1003 Peak Voltage RMS 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 0 20 40 60 80 100 120 140 Conduction Angle ( ) Normal Sine Wave RMS Voltage Power as Fraction of Full Conduction FULL WAVE Power AVG 180 160 Figure AN1003.4 Symmetrical Full-Wave Phase Control (Sinusoidal) Figure AN1003.3 and Figure AN1003.4 also show the relative power curve for constant impedance loads such as heaters. Because the relative impedance of incandescent lamps and motors change with applied voltage, they do not follow this curve precisely. To use the curves, find the full-wave rated power of the load, and then multiply by the ratio associated with the specific phase angle. Thus, a 180 conduction angle in a half-wave circuit provides 0.5 x full- wave conduction power. In a full-wave circuit, a conduction angle of 150 provides only 3% of full power control. Therefore, it is usually pointless to obtain conduction angles less than 30 or greater than 150. Figure AN1003.5 and Figure AN1003.6 give convenient direct output voltage readings for 115 V/230 V input voltage. These curves also apply to current in a resistive circuit. Peak Voltage 180 160 140 120 100 80 60 40 20 0 0 20 40 60 80 100 120 140 Conduction Angle ( ) RMS AVG Output Voltage 360 320 280 240 200 160 120 80 40 0 Input Voltage 230 V 115 V HALF WAVE 180 160 Figure AN1003.5 Output Voltage of Half-wave Phase Peak Voltage RMS 0 20 40 60 80 100 120 140 Conduction Angle ( ) AVG Output Voltage 360 320 280 240 200 160 120 80 40 0 Input Voltage 230 V 115 V 180 160 140 120 100 80 60 40 20 0 FULL WAVE 180 160 Figure AN1003.6 Output Voltage of Full-wave Phase Control Phase Control Using Thyristors (continued)

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