Recollect from the general characteristics of a BJT that values of V CE in the vicinity of 0.3 V indicate that the device is saturated - a situation that must not really exist unless of course if the BJT is working in a switching mode. While troubleshooting a BJT, another voltage level having equal significance is the collector-to-emitter voltage. Observe that the positive (red) lead of the digital multimeter is touched to the base terminal for an npn transistor and the negative (black) lead to the emitter terminal.Īny different form of display not matching the approximate 0.7 V, such as 0, 4, or 12 V, or a negative could be an indication of a faulty device, and the network connections might require a deeper analysis during such a situation.įor a pnp transistor, the very same strategy may be used however the meter probe polarity will need to be reversed for getting a similar response. The correct relationships for testing V BE can be seen in below shown Figure. įor a BJT that's in a switched ON condition, the voltage across its base and emitter V BE should be in the vicinity of 0.7 V. Remember, for any BJT in the active region, the most crucial measurable dc level is actually its base-to-emitter voltage V BE. Quite certainly, the initial step in having the ability to troubleshoot a BJT circuit would be to get thoroughly familiar with the tendencies of the network, and to have idea regarding the specified voltage and current ranges. BJT troubleshooting techniques is a huge topic and therefore including 100 % solutions and strategies can be perhaps difficult within a single article.īasically, the user should know about a handful of fundamental moves and measurements which may enable him to spotlight the location of the problem and help recognize the remedy.
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