User Manual
Table Of Contents
- Getting started
- Oscilloscope basics
- Analog versus digital:
- Waveforms:
- Measuring probe:
- Connecting the probe:
- Setting up the board:
- Experiment 1: Measuring AC voltage
- Connection layout:
- Connection summary:
- Purpose:
- How?:
- What we see:
- Experiment 2: Adjustable AC voltage
- Connection layout:
- Connection summary:
- Purpose:
- How?:
- Experiment 3: Measuring AC grid frequency and period
- Connection layout:
- Connection summary:
- Purpose:
- How?:
- Experiment 4: Rectified AC, single phase
- Connection layout:
- Connection summary:
- Purpose:
- How?:
- A little theory:
- Experiment 5: Rectified AC, dual phase
- Connection layout:
- Connection summary:
- Purpose:
- How?:
- A little theory:
- Exercise:
- Experiment 6: Smoothed versus unsmoothed DC (ripple)
- Connection layout:
- Connection summary:
- Purpose:
- A little theory:
- How?:
- Experiment 7: DC measurement
- Connection layout:
- Connection summary:
- Purpose:
- How?:
- Exercise:
- Experiment 8: Waveform with adjustable frequency
- Connection layout:
- Connection summary:
- Purpose:
- How?:
- How does it work?
- Exercise:
- What is the purpose of the ‘slope’-symbol?
10 11
Press the upper right button again to select vertical marker 2. Use the arrow keys to position
this marker at the exact same location but further to the right of the screen.
You have now selected one period or cycle of the
displayed waveform. In the lower right corner, the unit displays
the time between the two markers. In most cases, this will be
20ms (16.66ms). The value displayed is called the period of a
waveform, i.e. the time before it repeats itself.
Now for the frequency (=the number of periods per second).
Press and hold the upper right hand button until the menu ap-
pears.
When the menu appears, release the button and press it
again a number of times, until ‘time mark’ is displayed in
reverse video. Next, press any arrow key once to change the
mode from ‘time mark’ to ‘freq mark’. Release all buttons and
wait until the unit exits the menu.
Look in the lower right corner. The readout now displays
frequency. In most cases this will be 50Hz (60Hz).
Good to know: The AC power grid frequency in most parts of the world is 50Hz.
The US, Japan and some parts of Central and South America have 60Hz power
Experiment 4: Rectied AC, single phase
Connection layout:
Connection summary:
GND clip : 4
Probe tip : 5
Purpose:
ThepurposeofthisexperimentistoshowwhatsinglephaserectiedAClookslikeonascopescreen.
How?:
1. Turn on the HPS140 Handheld Pocket Scope (see HPS140 manual for How-To instructions).
2. Place the probe switch “x1/x10” to ‘x1’.
3. MakesuretoipSW1tothecorrectposition
Select 5ms/div and 4V/div.
The display will show a signal similar to this one:
A little theory:
With a single diode, we can convert an AC voltage to a DC voltage. As a diode only conducts the
current in one way, only one half of the waveform can pass. The other half, with inverted polarity, is
blocked. As you can see on the screen, the trace shows ‘interruptions’ where the voltage is 0. This is
the part of the AC voltage that is blocked by the diode. If you move the probe clip from test point 5 and
to test point 1, you remove the diode from the circuit and the display shows the complete waveform
again.
NOTES:
RectiedAC,singlephaseMeasuring AC grid frequency and period
Good to know: Shouldtherectierdiodebedefective,thenyouwillseeeitherthe
complete waveform (if the diode is shorted) or no waveform at all (if the diode is open-
circuit).