Laboratory Practical Announcement

The lab practical is 10% of your final grade. The lab practical will be held during the last week of class (Monday 04 to Thursday 07 Dec). You will sign up for a 30 min time slot during the afternoon of your regularly scheduled lab period. You are permitted a calculator. Pin outs for op amps will be provided for you. The resistor code will be provided.

Basic skills you will demonstrate.

• Using the Oscilloscope and scope probes to measure voltage, frequency, and phase (includes triggering).
• Using the DMM to measure voltage, current, and resistance.
• Using the function generator. Control of wave-form type, amplitude, frequency, and DC offset.
• Using the DC power supply. Some circuits require more than one voltage. You should be able to quickly set up the power supply to give multiple voltages (such as required for operational amplifiers) and to properly connect them to your circuit.

Circuits to may be asked to calculate and demonstrate.

• voltage divider
• high-pass filter
• low-pass filter.
• Operational Amplifier circuits: voltage follower, inverting amplifier, non-inverting amplifier, adder, differential amplifier, and current-to-voltage converter amplifier.

Examples of the types of questions you may be asked:

1) Construct and demonstrate a voltage divider that divides the voltage by 5. Drive the divider using the function generator so that the output of the divider is a 150 Hz, 100 mVpp square wave.
Measure the actual voltage division factor using the square wave just mentioned.

2) Construct a gain of 10 non-inverting amplifier. Drive the amplifier using the function generator so that the output of the divider is a 2 kHz 3Vpp sine wave.
Measure the actual gain of the amplifier at 2 kHz. and at DC.

3) Construct a 300 Hz RC high-pass filter.
Measure the frequency of the 3 dB point using the function generator and the oscilloscope.
Think of the RC filter as a frequency dependent voltage divider, at DC Vout/Vin = ? at infinite frequency Vout/Vin = ?

4) Measure the voltage and short circuit current of the battery with the DMM. Knowing that the internal resistance of the DMM is 10M in voltage mode and negligible in ammeter mode, calculate the open circuit voltage of the battery. (Hint: You need to make two measurements, a voltage measurement and a current measurement.)