Thyristor Semiconductor Products Page 33 Thyristor

2014 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 12/14/14 Teccor brand Thyristors AN1003 Load 120 V (60 Hz) R 2 R 6 R 7 R 3 R 5 R 4 R 8 D 2 D 1 D 6 D 3 R 1 D 5 Temp T 1 C 1 Q 1 D 4 Q 2 Triac "Gain" 0 Ramp Time Cool Hot UJT Triggering Level Pedestal UJT Emitter Voltage R 1, R 2 = 2.2 k, 2 W R 3 = 2.2 k, 1/2 W R 4 = Thermistor, approx. 5 k at operating temperature R 5 = 10 k Potentiometer R 6 = 5 M Potentiometer R 7 = 100 k, 1/2 W R 8 = 1 k, 1/2 W Q 1 = 2N2646 Q 2 = Q4010L5 T 1 = Dale PT 10-101 or equivalent D 1-4 = 200 V Diode D 5 = 20 V Zener D 6 = 100 V Diode C 1 = 0.1 F, 30 V Figure AN1003.13 Precision Proportional Temperature Control Several speed control and light dimming (phase) control circuits have been presented that give details for a complete 120 V application circuit but none for 240 V. Figure AN1003.14 and Figure AN1003.15 show some standard phase control circuits for 240 V, 60 Hz/50 Hz operation along with 120 V values for comparison. Even though there is very little difference, there are a few key things that must be remembered. First, capacitors and Triacs connected across the 240 V line must be rated at 400 V. Secondly, the potentiometer (variable resistor) value must change considerably to obtain the proper timing or triggering for 180 in each half-cycle. Figure AN1003.14 shows a simple single-time-constant light dimmer (phase control) circuit, giving values for both 120 V and 240 V operation. 0.1 F 200 V 0.1 F 400 V AC Input Voltage 120 V ac 60 Hz 240 V ac 50/60 Hz 12 A 3 A 250 k 500 k Q4010LTH Q6006LTH 100 H 200 H R 1 Q 1 L 1 C 1 , C 3 R 1 R 2 C 1 Diac 3.3 k AC Input C 2 Q 1 L 1 R 3 * 100 C 3 * Load Note: L 1 and C 1 form an RFI filter that may be eliminated * dv/dt snubber network when required 0.1 F 100 V AC Load Current Figure AN1003.14 Single-time-constant Circuit for Incandescent Light Dimming, Heat Control, and Motor Speed Control The circuit shown in Figure AN1003.15 is a double- time-constant circuit which has improved performance compared to the circuit shown in Figure AN1003.14. This circuit uses an additional RC network to extend the phase angle so that the Triac can be triggered at small conduction angles. The additional RC network also minimizes any hysteresis effect explained and illustrated in Figure AN1003.10 and Figure AN1003.11. 0.1 F 200 V 0.1 F 400 V 0.1 F 400 V AC Input Voltage 120 V ac 60 Hz 240 V ac 50 Hz 240 V ac 60 Hz 8 A 6 A 6 A 250 k 500 k Q4010LTH Q6008LTH 100 H 200 H 200 H R 2 Q 1 L 1 C 1 , C 2 , C 4 R 2 R 1 C 1 Diac 3.3 k AC Input C 2 Q 1 L 1 R 4 * 100 C 4 * Note: L 1 and C 1 form an RFI filter that may be eliminated * dv/dt snubber network when required R 3 0.1 F 100 V 15 k 1/2 W C 3 Load AC Load Current Figure AN1003.15 Double-time-constant Circuit for Incandescent Light Dimming, Heat Control, and Motor Speed Control Phase Control Using Thyristors (continued)

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