# User:Tyler Wynkoop/Notebook/Junior Lab/Week 1

### From OpenWetWare

## **Oscilloscope Lab Procedure Notes**

^{SJK 14:48, 24 September 2010 (EDT)}Procedure Page: Physics307L:Labs/Oscilloscope

**Step 1**

^{SJK 14:36, 24 September 2010 (EDT)}- Tune FG to 200 Hz
- Use BNC cable [1]

**Step 2**

Fiddle with Osc and FG settings to get best sine image as follows:

- 500 Hz
- DC offset off
- Output level about one quarter max
- Trigger at 0; rising
- Zoom at 1.00V

**Step 3**

Measuring the sine wave parameters

- Using the grid lines on the Osc
- Amplitude approx. 3.61V
- Period approx. 2.00ms

- Using cursors
- Amplitude 3.64V
- Period 2.000ms

- Using the measure function
- Amplitude 3.68V
- Period 2.000±.004ms

**Step 4**

Triggering

- Triggering (in my own words) is at what voltage, in the sine wave, that the Osc begins to measure the waveform. The Osc must be told first whether to begin measuring the voltage as the wave form rises or falls.

AC/DC Coupling

- DC coupling allows both DC and AC voltage through to be viewed and measured, AC coupling only allows the AC voltage through. AC coupling can reveal sublties in the voltage that can be masked by DC voltage.

**Step 5**

- Fall Time:

Fall time is the characteristic time of the capacitor in the AC coupler in the oscilloscope. It is the time constant (τ) the exponential decay of the voltage across the capacitor represented by the equation:

*V*_{0} = *V*_{max} * *e*^{ − t / τ}

To find this number, I first changed the FG to display square waves. Secondly, I set the coupling to AC (in order to use the capacitor being measured). Finally, I DC lowered the number of cycles per second (Hz) on the FG to just over 8, to allow the capacitor to fully discharge after each pulse.

- With cursors, the estimated value is 53.00 ms
- With the measure function, the value is 55.6±.3ms