To design a transistor inverter and investigate the switching characteristics

To design a transistor inverter and investigate the

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To design a transistor inverter and investigate the switching characteristics of BJTs and MOSFETs. Pre-Lab: Acquire the necessary parts to perform the experiment. List of Parts: 1. A 2N3904 BJT and a 2N7000 MOSFET 2. A variety of resistors from 100ohm to 100Kohm 3. Alternately obtain a CD4007 integrated circuit which contains 3 ea. N-Channel and P- Channel MOSFETs. Procedure: 1) Build the inverter circuit shown in Figure 1 on the PCB. Choose proper value for R L and R B . Drive the transistor with a voltage pulse and observe the output voltage signal. The transistor must be driven into saturation or near saturation when the input signal is high . 2) Select an input pulse width much larger than the response time of the transistor so that you can observe both the turn-on and turn-off transients. 3) Display both the input and output signals on the oscilloscope, compare them and comment on the time delay (with respect to the input signal) incurred at the output signal during turn- on and turn-off transitions. 4) Repeat the same things using an MOS transistor as the switching device. Post Lab: Plot the input and output waveform for both BJT and MOSFET transistors. You should also indicate what the rise and fall times are. Would these transistors be fast enough for a 3 GHz circuit?
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CALIFORNIA STATE POLYTECHNIC UNIVERITY, POMONA Electrical and Computer Engineering Department ECE 220 Lab Experiment #9 Page 2 of 2 Figure 1. A transistor invertor circuit
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CALIFORNIA STATE POLYTECHNIC UNIVERITY, POMONA Electrical and Computer Engineering Department ECE 220 Lab Experiment #10 Page 1 of 2 Current-Voltage Characteristics of the Junction Field Effect Transistor Objective: To study the relationships between the terminal currents and terminal voltages in the Junction Field Effect Transistor (JFET). A JFET is another useful 3-terminal device that has structure and characteristics very similar to Metal Semiconductor Field Effect Transistors (MESFET) used in high-speed III-V compound-based semiconductor devices. Pre-Lab: Obtain the necessary parts from the parts list. Be sure to obtain a pin diagram for the LM741 Operational Amplifier (OPAMP) and build the circuit in Figure #1 prior to coming to the lab. Make sure you understand how the circuit works and how it enables the display of I DS vs. V DS on the screen of the oscilloscope. It is essential to remember that the gate voltage is NEVER to be positive, this in order to prevent the PN junction between the gate and the channel from becoming forward biased. List of Parts: 1. A 2N3819 or NTE312 (or equivalent) JFET 2. A LM741 (or equivalent) OPAMP 3. Resistors; 100 1K 100K : Procedure: 1) Figure 1: Before connecting the function generator to the circuit, connect it directly to the oscilloscope and set its output to 10V (p-p) triangle wave offset to +5V DC. The resultant waveform should ramp from 0 to +10V and back to 0. Set the frequency of the waveform to approximately 80 - 100Hz. The signal generator will now act as an automatically varying drain supply to the JFET as V DD .
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  • Spring '08

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