COMPONENT_CHECKER

Published:2009/7/16 3:27:00 Author:Jessie | From:SeekIC

The circuit is a component checker that works by lighting corresponding LEDs. If you insert a transistor's B and E leads (or a shorted transistor) into the C and E sockets, an LED will light, but you will know that the transistor is placed in the wrong position because the proper LED should light only when you press S1. You might want to use five sockets placed C-E-B-C-E to avoid bend-ing the transistor leads. A bicolor LED can be used instead of the two plain LEDs shown. With the transistor-lead sockets you can also check SCRs, LEDs, etc. For SCRs, place the polarity switch in the NPN position, and insert the A, K, and G leads in the C, E, and B sockets, respectively. Momentarily press S1 and the NPN LED should light and stay on when you release the switch. To check LEDs, place the polarity switch in the NPN position, and insert the LED's anode and cathode in the B and E sockets, respectively. Pressing S1 should cause a good LED under test to light. Two more sockets, labeled + and -, can be used to check diodes, continuity, capacitors, etc. To check a diode, place the polarity switch in the NPN position and place the anode and cathode of the diode into the + and - sockets. Press S1, and the NPN LED should light. To check continuity, place the polarity switch in any position, insert test leads into the + and - sockets, press S1, and a polarity LED should light if the path under test conducts. To check capacitors, insert the capacitor leads with the correct polarity in the + and - sockets. Then rapidly change the polarity to PNP, then to NPN, then back to PNP. The LEDs should light alternately. This test checks only charge and discharge, not capacitance.



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