Thyristor Semiconductor Products Page 55 Thyristor

2014 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 12/14/14 Teccor brand Thyristors AN1006 8 A or less should be tested on standard curve tracer. If testing devices above 8 A, a Tektronix model 176 high- current module is required. Kelvin fixture is not used, an error in measurement of V TM will result due to voltage drop in fixture. If a Kelvin fixture is not available, Figure AN1006.3 shows necessary information to wire a test fixture with Kelvin connections. Procedure 5: V TM (Forward) To measure the V TM (Forward) parameter: 1. Set Polarity to (+). 2. Set Left-Right Terminal Jack Selector to correspond with location of test fixture. 3. Increase Variable Collector Supply Voltage until current reaches rated I T(peak) , which is 1.4 times I T(RMS) rating of the Triac under test. Note: Model 370 current is limited to 10 A. WARNING: Limit test time to 15 seconds maximum. After the Variable Collector Supply Voltage has been set to I T(peak) , the test time can automatically be set to a short test time by changing Step Family from repetitive to single by depressing the Single button. To measure V TM , follow along horizontal scale to the point where the trace crosses the I T(peak) value. The distance from the left-hand side of scale to the crossing point is the V TM value. (Figure AN1006.12) 500 mV V E R T H O R I Z S T E P V TM I PK 2 A 100 mA 20 Figure AN1006.12 V TM (forward) = 1.1 V at I PK = 11.3 A (8 A rms) Procedure 6: V TM (Reverse) To measure the V TM (Reverse) parameter: 1. Set Polarity to (-). 2. Set Left-Right Terminal Jack Selector to correspond with the location of the test fixture. 3. Increase Variable Collector Supply Voltage until current reaches rated I T(peak) . 4. Measure V TM(Reverse) from upper right hand corner of screen. Procedure 7: I H(Forward and Reverse) To measure the I H (Forward and Reverse) parameter: 1. Set Step/Offset Amplitude to twice the I GT rating of the device. 2. Set Power Dissipation to 10 W . 3. Set Max Peak Volts to 75 V. ( 80 V on 370) 4. Set Mode to DC. 5. Set Horizontal knob to Step Generator . 6. Set Vertical knob to approximately 10% of the maximum I H specified. Note: Due to large variation of holding current values, the scale may have to be adjusted to observe holding current. 7. Set Number of Steps to 1. 8. Set Step/Offset Polarity to non-inverted (button extended, on 577 button depressed). 9. Set Offset by depressing 0 (zero). (Press Aid and Oppose at same time on 370.) 10. Set Terminal Selector to Step Generator-Emitter Grounded. Procedure 8: I H(Forward) To measure the I H (Forward) parameter: 1. Set Polarity to (+). 2. Set Left-Right Terminal Jack Selector to correspond with location of test fixture. 3. Increase Variable Collector Supply Voltage to maximum position ( 100 ). 4. Set Step Family by depressing Single. This could possibly cause the dot on the CRT to disappear, depending on the vertical scale selected). 5. Decrease Variable Collector Supply Voltage to the point where the line on the CRT changes to a dot. The position of the beginning point of the line, just before the line becomes a dot, represents the holding current value. (Figure AN1006.13) 5 mA 100m V E R T H O R I Z S T E P 50 mA I H Figure AN1006.13 I H (Forward) = 8.2 mA Thyristor and Rectifier Testing Using Curve Tracers (continued)

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