FINDING THE HYSTERESIS CHARACTERISTIC OF AN EMITTER-COUPLED CIRCUIT An emitter-coupled Schmitt trigger circuit is shown in Figure 15.1(a). Plot the hysteresis characteristics of the circuit from the results of transient analysis. The input voltage, which is varied slowly from 1.5 to 3.5 V and from

Question

FINDING THE HYSTERESIS CHARACTERISTIC OF AN EMITTER-COUPLED CIRCUIT

An emitter-coupled Schmitt trigger circuit is shown in Figure 15.1(a). Plot the hysteresis characteristics of the circuit from the results of transient analysis. The input voltage, which is varied slowly from 1.5 to 3.5 V and from 3.5 to 1.5 V, is as shown in Figure 15.1(b). The model parameters of the transistors are IS = 2.33E− 27, BF = 13, CJE = 1PE, CJC = 607.3PF, and TF = 26.5NS. Print the job statistical summary of the circuit.

Accepted Answer

The input voltage is varied very slowly from 1.5 to 3.5V and from 3.5 to 1.5V as shown in Figure 15.1(b).

The PSpice schematic is shown in Figure 15.2(a). The ACCT option is selected from the Options menu as shown in Figure 15.2(b).

The listing of the circuit file is as follows:

Example 15.1 Emitter-coupled trigger circuit

SOURCE VDD 5 0 DC 5V ; DC supply voltage of 5V

VIN 1 0 PWL (0 1.5V 2 3.5V 4 1.5V) ; PWL waveform

CIRCUIT R1 5 2 4.9K

R2 5 3 3.6K
RE 4 0 1K
Q1 2 1 4 4 2N6546    ; Transistor Q1
Q2 3 2 4 4 2N6546     ; Transistor Q2
.MODEL 2N6546 NPN (IS=2.33E−27 BF=13 CJE=1PF CJC=607.3PF
TF=26.5NS)
.OPTIONS ACCT                                    ; Printing the accounts summary

ANALYSIS .TRAN 0.01 4 ; Transient analysis form 0

to 4 s in steps of 0.01 s
.PROBE ; Graphics post-processor

.END

The hysteresis characteristic for Example 15.1 is shown in Figure 15.3. The default x axis for transient analysis is time. The x-axis setting as shown in Figure 15.3 is changed from the x-axis setting of the Plot menu in Probe. The job statistical summary, which is obtained from the output file, is as follows:

*** JOB STATISTICS SUMMARY
NUNODS NCNODS NOMNOD NUMEL DIODES BJTS JFETS MFETS GASFETS

6 6 6 7 0 2 0 0 0

NDIGITAL NSTOP NTTAR NTTBR NTTOV IFILL IOPS PERSPA

0 8 23 23 54 0 36 64.063

NUMTTP NUMRTP NUMNIT DIGTP DIGEVT DIGEVL MEMUSE

210 40 896 0 0 0 9914

	SECONDS	ITERATIONS
MATRIX SOLUTION	.77	5
MATRIX LOAD	4.42
READIN	.50
SETUP	.11
DC SWEEP	0.00	0
BIAS POINT	.99	92
AC and NOISE	0.00	0
TRANSIENT ANALYSIS	9.56	896
OUTPUT	0.00
TOTAL JOB TIME	10.54

Question 15.1: FINDING THE HYSTERESIS CHARACTERISTIC OF AN EMITTER-COUPLED ...

Related Answered Questions

PROVIDING DC PATHS TO A PASSIVE FILTER A passive filter is shown in Figure 15.14. The output is taken from node 9. Plot the magnitude and phase of the output voltage separately against the frequency. The frequency should be varied from 100 Hz to 10 kHz in steps of one decade and 101 points per ...

Verified Answer:

TRANSIENT RESPONSE OF A SINGLE-PHASE FULL-BRIDGE INVERTER WITH VOLTAGE-CONTROLLED SWITCHES A single-phase bridge-resonant inverter is shown in Figure 15.8. The transistors and diodes can be considered as switches whose on-state resistance is 10 mΩ and whose on-state voltage is 0.2 V. Plot the ...

Verified Answer:

TRANSFER FUNCTION ANALYSIS OF A CIRCUIT WITH A NEGATIVE RESISTOR A circuit with negative components is shown in Figure 15.5. The input voltage is Vin = 120 V (peak), 60 Hz. Use PSpice to calculate the currents I(R1), I(R2), and I(R3) and the voltage V(2). ...

Verified Answer: