Compare your result with the calculated transresistance, r tr = 26 mv/i E where I E is the average of the two values from step Using the transistor curve tracer, measure the collector characteristics of your transistor. Calculate h fe = I E / I B from the measurements taken in step 4 and determine the transresistance. As discussed in class, the input impedance is related to h fe (or β) and a quantity called the transresistance according to r in = h fe r tr. Calculate h ie for your transistor from: h = V / I constant V ie BE B CE A typical value for this parameter is 3.5 kω. Keeping V CE constant (at 8 V for example) set I B to 6 µa and then l0 µa, and record the values of I E and V BE at each point. re BE CE B Typical values for these parameters are h oe ~ 10-4 S and h re ~ 5-10 x The input impedance of the transistor (h ie or r in ) can be measured as follows. 2ģ Calculate the output admittance, and the reverse voltage ratio, h = I / V constant I, oe E CE B h = V / V constant I. Then adjust the power supply and the pot to get V CE = 16 V and the same value of I B that you had for the first measurement, and record the parameters again. Record the values of I E, I B, V BE and V CE. Adjust the power supply voltage V 0 to obtain V CE = 8 V, and then adjust the 10 kω pot to get I B 15 µa. In this step we will measure two parameters, the output admittance (h oe ) and the reverse voltage ratio (h re ) that give the sensitivity of I E and V BE to changes in V CE. The quantities I E and V BE are approximately independent of V CE. How does your result compare with the expected value, V kt = kt/e = 26 mv? 3. Determine the quantity V kt from the slope of the linear part of the graph, assuming that V BE /V kt 1. constant temperature) portion of the graph is linear. Make a graph of I E vs V BE on semilog paper, and verify that the low-current (i.e. For signal transistors such as the one we use in this experiment, the relationship between V BE and I E (or I C ) is given approximately by: E 0 ( V BE /V kt ) I = I e 1 provided that T is constant (I 0 and V kt both depend on temperature). Calculate h FE (or β) at each point from the formula β = I E /I B and make a graph of β as a function of I E. You may reset V CE to 12 V at each step if you want, but it is also all right to just ignore the changes, since I E and V BE are nearly independent of V CE. You will also notice that V CE changes some (particularly when you change scales on the ammeter I E ). After each change in I B you should pause briefly ( 1 minute) to allow the temperature to stabilize before taking the readings. This drift is due to the temperature change caused by the power dissipation in the transistor. You will notice that V BE drifts slowly for some time after I B is increased or decreased. Measure and tabulate I E and V BE as a function of I B taking 2 µa steps for 0 I B 10 µa and 5 µa steps for 10 µa I B 50 µa. By adjusting the pot you can change the base-toemitter voltage, V BE, and hence the base current I B. Make the remaining connections, and then turn on the power supply and adjust V 0 so that V CE = 12 V. Next, connect the ammeters being careful to observe the proper polarity and then connect up the power supply, again being careful to observe the polarity.
#How to test a 2n3055 transistor full#
Turn the 10 kω pot all the way down (i.e., full counter-clockwise). The first step is to measure I E and V BE as a function of the base current for a fixed value of V CE. Use digital meters to measure the voltages V BE and V CE. For ammeter I B use a VOM on the 0-50 µa scale for I E use a second VOM with the scale set to 1, 10, or 100 ma as needed. THE BIPOLAR TRANSISTOR The circuit we will use to measure the properties of a silicon PNP transistor (model 2N3906) is shown below. VIEW FROM ABOVE (leads point away from you) BIPOLAR FET I.
#How to test a 2n3055 transistor install#
Be sure to observe the proper orientation of leads when you install the transistors in the test setup and the curve tracer. 1 EXPERIMENT 9: BIPOLAR AND FIELD EFFECT TRANSISTOR CHARACTERISTICS In this experiment we will study the characteristics of bipolar and junction field-effect (JFET) transistors, and will learn to use the transistor curve tracer.