Name of the exercise: Astable Multivibrator (Square or Rectangular wave generator)
Aim: To simulate Astable Multivibrator (Square or Rectangular wave generator)
1. MULTISIM Software Loaded PC 1 No.
2. Printer 1 No.
2. NE555 IC Pin details.
3. Design Circuit.
4. Simulation Procedure.
5. Output Waveform.
Astable Multivibrators are free running oscillators which oscillate between two states continually producing two square wave output waveforms
• Open MULTISIM Software.
• Click=> New => Design1
• Click save as in Desk Top rename the Design1 to your circuit name.
• Go to Component tool bar and select the components.
• Draw the circuit diagram of astable multivibator using NE555 IC.
• Connect the CRO above mentioned circuit.
• Click simulate button or press F5 key => RUN
• Note down the Time period and calculate the frequencies.
• Record the output waveforms.
The astable multivibrator is designed and its output is verified using MULTISIM software, measured Square and Rectangular wave waveforms.
Questions with answers:
1. What is a 555 IC?
The 555 IC is a highly stable device that can be used for generating accurate time delays or oscillations.
2. How to calculate frequency and duty cycle of an astable multivibrator output?
Frequency = 1/T = 1/TON + TOFF
Duty cycle = TON/T * 100 = (TON/(TON+TOFF)) *100\
3. What is called frequency and duty cycle?
Frequency is the number of complete cycles per second.
Duty cycle is the percentage of the ratio of the pulse duration to the total time period.
A duty cycle of 60% means out of the total time period 60% is high state or the active state and the rest of 40% is in a low state.
4. Applications of Astable Multivibrators.
The applications of Astable multivibrators involve in radio gears to transmit and receive radio signals and also in time, morse code generators and some systems which require a square wave like analog integrated circuits and TV broadcasts.
All experiments should be designed and verified through simulation tools like Multisim.
1. Zener diode (Forward and Reverse bias characteristics)
2. Rectifier circuits ( Half wave, Full wave, Bridge rectifier with filters)
3. Power supply with Zener diode as Regulator
4. Common Base transistor output characteristics
5. Common emitter amplifier (Implementation of Current Series negative feedback)
6. Emitter follower (Implementation of Voltage Series negative feedback)
7. RC Coupled amplifier (Implementation of the concept of multistage amplifier)
8. Clippers and Clampers
9. RC Phase shift oscillator (Medium frequency Sine wave generators)
10. Hartley oscillator (High frequency Sine wave generator)
11. Astable Multivibrator (Square or Rectangular wave generator)
12. Gate triggering of SCR with various gate currents.