EE 2212

EXPERIMENT 10

15 April  2021

THE EMITTER-COUPLED PAIR

PURPOSE

Note 1:      Experiment 10   will not be collected but I will look for the work in your  Laboratory Notebook.  A comprehensive notebook review is scheduled for Thursday, 22 April. 

The purpose of this experiment is to characterize the  properties of an emitter-coupled pair:

·             DC Biasing

·             Time Domain Measurements

 COMPONENTS

Ø         LM3046/CA3046 transistor array.  The data sheet is also posted on the class WEB page LM3046NationalSemiconductor.pdf  This is the IC you used last week.

Ø         47 kW resistor for each collector

Ø         REE for you to design for DC biasing.  We do not have an infinite variety of resistors which means you will have make reasonable adjustments to the design specifications.

GENERAL INFORMATION

Ø    Figure 10.1 is a pin out of the LM3046/CA3046/3045 Transistor Array. Observe that you MUST connect Pin 13, the IC substrate,  to the most negative point in the circuit or bad things happen to the IC.  The most negative point is the VEE-REE node, not ground!  Refer to Figure 10.2

expt8nr1

Figure 10.1 LM3046/CA3046/3045

 NPN BJT ARRAY

Use Figure 10.2  and class notes for guidance to prepare a detailed circuit diagram.   Include  pinouts for  the LM3046/CA3046 npn array. From your circuit diagram and circuit specifications, calculate the expected important   Q-point values  and Adm .

DC MEASUREMENTS

Refer to the diagram and data sheet of the LM 3046/CA3046 BJT array.

Set up the circuit in Figure10.2  using Q1 and Q2 on the LM3046 IC for the emitter-coupled pair.  Lead dress and length is also important.  Be neat! 

Design a value for REE such that the ICQ1 and ICQ2 are about 100 μA.   

·        Ground both the inputs of Q1 and Q2. That is do not connect the HANTEK AWG for the DC set-up.

·        Verify that both battery packs are turned on. 

·        Measure the all Q-point voltages and currents using the DMM.   Also measure the VCC and VEE voltages to be sure there is still some battery life!   Some of you had dead batteries last week.   Compare your Q-point values with the expected and SPICE simulations. 

Figure 10.2

·        Compute the expected Adm = vod/vid for the circuit so that you can set the HANTEK AWG to a reasonable amplitude to minimize clipping.

·        Connect the AWG as shown in Figure 10.2.  Set f=100 Hz and the desired amplitude.

·        Connect Channel 1 to vo1 and Channel 2 to vo2 and Auto scale.

·        Also  observe that because  the oscilloscope does not have a   floating input (i.e., one  side of each of the two oscilloscope inputs are  connected to ground), you will have to measure either VO1  or VO2 and scale the final results accordingly by a factor of 2 and also do not forget the sign (180°phase) difference between  each of the outputs. 

·        You can not connect one probe across vod because one side of the probe is grounded through the coaxial cable.

·        Observe what happens when you increase the AWG signal input level.

·        Compare your results to a SPICE transient simulation and analysis.

A bit of EE humor.

This guy deserves a tip!

And for those of you who go to Buffalo Wild Wings and

try their “Blazin” ghost pepper suace

You might cover conformal mapping from an advanced math course

 when using Smith Impedance Charts

in EE 3445 or the Antenna and Transmission Line Course