555 Timer

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As one of the most widespread ICs, the 555 timer has huge range of applications. This Experiment Card explores the 555’s modes of operation, and the assignment guide takes the student through circuit construction and testing to develop their understanding of this versatile chip.

Typical topic areas include:

• 555 Timer Characteristics
• Monostable (Delay) Operation
• Astable Multivibrator
• Astable Multivibrator Frequency
• Duty Cycle Control Operation
• Reset Functions

Typical activities include:

• Investigate the effect of the Trigger input on the Output of a 555 Timer.
• Identify the operation of the Discharge output on a 555 Timer.
• Sketch the input and output waveforms of a 555 Timer monostable.
• Calculate the duration of the output pulse of a 555 Timer monostable.
• Investigate the effect of varying the values of the capacitor and resistor in a charging circuit for a 555 Timer.
• Calculate the charging and discharging times for an astable multivibrator from the C and R values in the timing circuit.
• Measure the charging and discharging times for an astable multivibrator.
• Measure the effect of changing the value of the capacitor in the timing circuit of an astable multivibrator.
• Measure the effect of changing the value of the resistor in the timing circuit of an astable multivibrator.
• Define Duty Cycle and Mark:Space ratio.
• Investigate the effect of a Reset input pulse on the operation of a fast astable multivibrator.

This resource includes:

• Experiment Card
• Assignment Guide
• Storage Case