Scr-tester
The cathode, anode, and gate of the Device Under Test (DUT) are connected to the unit's K, A, and G terminals, respectively. Pressing switch S1 supplies a gate current to the DUT, triggering it to turn on. Resistor R1 limits the gate current to an appropriate level. Resistor R3 restricts the current through the LED to approximately 20 mA, which, along with the current through R2, results in a latching current of about 110 mA. The LED is used to monitor the latching current. If the DUT is functioning properly, once the gate is triggered with S1, the LED will remain illuminated, indicating that the device is conducting. To terminate the test, turn off the device by interrupting the latching current flow using switch S2. The LED should turn off and remain off. The preceding procedure is applicable for SCRs and triacs. To test LEDs and other diodes, connect the anode and cathode leads to the anode and cathode of the diode; LED1 should light up. When the leads are reversed, the LED should remain off.
The circuit described involves a test setup for semiconductor devices, specifically focusing on SCRs, triacs, and diodes. The DUT's connections to the K, A, and G terminals facilitate the necessary electrical parameters for testing.
Upon pressing switch S1, a gate current is directed through resistor R1, which is crucial for controlling the amount of current entering the gate of the DUT. This current must be limited to prevent damage to the DUT, ensuring it operates within its specified limits. Resistor R3 is strategically placed to limit the current flowing through the LED to about 20 mA, which is a standard operational current for most indicator LEDs, ensuring longevity and reliability.
The latching current, generated through the coordination of R2 and R3, is set to approximately 110 mA. This current is essential for maintaining the DUT in its 'on' state after the initial triggering by S1. The LED serves a dual purpose in this circuit: it acts as an indicator for the latching current and provides a visual confirmation that the DUT is functioning correctly. A lit LED signifies that the DUT is conducting, while its extinguishment indicates a failure in the conduction path or an interruption in the latching current.
To conclude the testing process, switch S2 is utilized to break the flow of the latching current, effectively turning off the DUT. This action should result in the LED turning off, confirming that the DUT is no longer conducting.
In addition to SCRs and triacs, the circuit can also be adapted for testing standard diodes and LEDs. By connecting the leads of the diode under test in the correct orientation, LED1 will illuminate, confirming the diode's functionality. Conversely, reversing the leads should keep the LED off, indicating a non-conductive state, which is expected behavior for a diode in reverse bias.
This schematic effectively demonstrates the principles of testing semiconductor devices, ensuring that key parameters such as current limits and operational states are adhered to, providing a reliable means of assessing device functionality.The DUT"s(Device Under Test) cathode, anode, and gate are connected to the unit"s K, A, and G terminals, respectively. Pressing switch ·Sl feeds a gate current to the D UT, which triggers it on. Resistor Rl limits the gate current to the appropriate level. Resistor R3 limits the current through the LED to about 20 mA, which, with the current through R2, results in a latching current of about 110 mA.
The LED is used to monitor the latching current. U the DUT is good, once the gate is triggered with Sl, the LED will remain lit, indicating that the device is conducting. To end the test, turn off the device by interrupting the latching current flow using switch S2. The LED should turn off and remain off. The preceding procedure will work with SCRs and triacs. Th check LEDs and other diodes, connect the anode and cathode leads to the anode and cathode of the diode; LED1 should light. When the leads are reversed, the LED should remain off. 🔗 External reference
The circuit described involves a test setup for semiconductor devices, specifically focusing on SCRs, triacs, and diodes. The DUT's connections to the K, A, and G terminals facilitate the necessary electrical parameters for testing.
Upon pressing switch S1, a gate current is directed through resistor R1, which is crucial for controlling the amount of current entering the gate of the DUT. This current must be limited to prevent damage to the DUT, ensuring it operates within its specified limits. Resistor R3 is strategically placed to limit the current flowing through the LED to about 20 mA, which is a standard operational current for most indicator LEDs, ensuring longevity and reliability.
The latching current, generated through the coordination of R2 and R3, is set to approximately 110 mA. This current is essential for maintaining the DUT in its 'on' state after the initial triggering by S1. The LED serves a dual purpose in this circuit: it acts as an indicator for the latching current and provides a visual confirmation that the DUT is functioning correctly. A lit LED signifies that the DUT is conducting, while its extinguishment indicates a failure in the conduction path or an interruption in the latching current.
To conclude the testing process, switch S2 is utilized to break the flow of the latching current, effectively turning off the DUT. This action should result in the LED turning off, confirming that the DUT is no longer conducting.
In addition to SCRs and triacs, the circuit can also be adapted for testing standard diodes and LEDs. By connecting the leads of the diode under test in the correct orientation, LED1 will illuminate, confirming the diode's functionality. Conversely, reversing the leads should keep the LED off, indicating a non-conductive state, which is expected behavior for a diode in reverse bias.
This schematic effectively demonstrates the principles of testing semiconductor devices, ensuring that key parameters such as current limits and operational states are adhered to, providing a reliable means of assessing device functionality.The DUT"s(Device Under Test) cathode, anode, and gate are connected to the unit"s K, A, and G terminals, respectively. Pressing switch ·Sl feeds a gate current to the D UT, which triggers it on. Resistor Rl limits the gate current to the appropriate level. Resistor R3 limits the current through the LED to about 20 mA, which, with the current through R2, results in a latching current of about 110 mA.
The LED is used to monitor the latching current. U the DUT is good, once the gate is triggered with Sl, the LED will remain lit, indicating that the device is conducting. To end the test, turn off the device by interrupting the latching current flow using switch S2. The LED should turn off and remain off. The preceding procedure will work with SCRs and triacs. Th check LEDs and other diodes, connect the anode and cathode leads to the anode and cathode of the diode; LED1 should light. When the leads are reversed, the LED should remain off. 🔗 External reference