Basic circuit or cad
- 1. Basic Circuit Simulation using OrCAD Prof. Anish Goel
- 2. Capacitors in Series Series Capacitors add like Parallel Resistors: 1/CT = 1/C1 + 1/Cn CT = .909uF 2 OrCAD Prof. Anish Goel
- 3. Capacitors in Parallel Parallel Capacitors add like Series Resistors: CT = C1 + Cn CT = 11uF 3 OrCAD Prof. Anish Goel
- 4. Inductors in Series • Series Inductors add like Series Resistors: • LT = L1 + Ln • LT = 11uH 4 OrCAD Prof. Anish Goel
- 5. Inductors in Parallel Parallel Inductors add like Parallel Resistors: 1/LT = 1/L1 + 1/Ln LT = .909uH 5 OrCAD Prof. Anish Goel
- 6. Capacitor Review Starts as short circuit, ends as open circuit iC = C*dVC/dt Open circuit at low frequencies Short circuit at high frequencies 6 OrCAD Prof. Anish Goel
- 7. Inductor Review Starts as open circuit, ends as short circuit VL = L*dI/dt Short circuit at low frequencies Open circuit at high frequencies 7 OrCAD Prof. Anish Goel
- 8. Filters Use frequency response characteristics of C and L to filter frequency components out of a time domain signal. Low Pass High Pass Band Pass Band Stop 8 OrCAD Prof. Anish Goel
- 9. Low Pass Filters RC Low Pass: fcut off frequency = 1/(2πRC) • Component selection • RC vs. RL filters RL Low Pass: fc = R/(2πL) 9 OrCAD Prof. Anish Goel
- 10. AC Analysis (freq) Logarithmic plot (count by decades) fc defined as –3dB of input, “Half power point” Copy paste data points to excel! 10 OrCAD Prof. Anish Goel
- 11. Decibels Measure of gain. Instead of saying gain is 100,000x, some engineers prefer to say it as 100dB. Power gain: dB = 10 log(Po/Pi) Voltage gain: dB = 20 log(Vo/Vi) Always a relationship 11 OrCAD Prof. Anish Goel
- 12. Decibels (cont’d) Useful values: 0dB = 1x 3dB = 2x 6dB = 4x 10dB = 10x 20dB = 100x 30dB = 1000x 3dBm is 3dB above 1mW 12 OrCAD Prof. Anish Goel
- 13. Cursor Control Cursor 1: left click left/right arrows Cursor 2: right click Shift left/right arrows 13 OrCAD Prof. Anish Goel
- 14. Cursor, Mark Label 14 OrCAD Prof. Anish Goel
- 15. .707? Because we are comparing gains in voltage, not power, we must use 20log(Vo/Vi). 10^(-3dB/20) = .707V So,Vo = .707Vi at the cut off frequency 15 OrCAD Prof. Anish Goel
- 16. Bode Plot (dB, logarithmic) 16 OrCAD Prof. Anish Goel
- 17. Common Problems Q: Simulation not making sense A: Make sure you how things are connected. 17 OrCAD Prof. Anish Goel
- 18. • RC High Pass: • RL High Pass: • fc = 1/(2πRC) • fL = R/(2πL) 18 OrCAD Prof. Anish Goel
- 19. Band Pass HP LP BW = (fc + 3dB) – (fc – 3dB) BW = 200.171kHz – 494.694Hz = 199.676kHz 19 OrCAD Prof. Anish Goel
- 20. Response 20 OrCAD Prof. Anish Goel
- 21. Band Stop HP LP BW = 16.216kHz –6.0833kHz = 10.133kHz 21 OrCAD Prof. Anish Goel
- 22. Response 22 OrCAD Prof. Anish Goel
- 23. Transformer Easy to “Step down” or “Step up” an AC voltage (This is why AC is used for home power delivery instead of DC.) VP/VS = NP/NS => VS = VPNS/NP Excellent DC filter because VS = NS*dΦ/dt 23 OrCAD Prof. Anish Goel
- 24. In PSPICE… Coupling = 1 Lx_Value = Nx2 should be between 1mH and 1H 24 OrCAD Prof. Anish Goel
- 25. Diode Allow current to flow only in 1 direction Flow from left (annode+) to right (cathode-) is forward biased. Diode causes a voltage drop due to its activation voltage. Silicon - .7V Germanium - .3V Cathode connected to a battery is reversed biased. (blocked) Perform DC Sweep and Transient Response (use D1N4002) 25 OrCAD Prof. Anish Goel
- 26. Activation Voltage 26 OrCAD Prof. Anish Goel
- 27. Transient Response Half Wave Rectifier 27 OrCAD Prof. Anish Goel
- 28. Half Wave Rectifier 28 OrCAD Prof. Anish Goel
- 29. Full Wave Rectification 29 OrCAD Prof. Anish Goel
- 30. Bridge Rectifier 30 OrCAD Prof. Anish Goel
- 31. In PSPICE… 31 OrCAD Prof. Anish Goel
- 32. Full Wave Rectifier 32 OrCAD Prof. Anish Goel
- 33. Smoothing Use capacitor to smooth the ripples of the rectified wave form. (Negative voltage) 33 OrCAD Prof. Anish Goel
- 34. Regulators Not in student addition Outputs a clean regulated voltage LM317 and 337 are +/- 2-18V variable regulators LM7805 is 5V regulator Input must be relatively steady or else regulator will fail. 34 OrCAD Prof. Anish Goel