EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: albe on July 28, 2013, 02:10:35 pm
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Hi all,
I am a newcomer to electronics and I wonder if I could seek advice on some questions on a second hand Hameg 303-6 that I have just purchased. Apologies in advance if the questions are numpty.
1. The probe compensation process in the Hameg involves setting the Voltage/Div to 5mv/DIv and the Time/Div to 0.2ms/Div for the 1kHz square wave signal generated by the scope's internal generator. At these settings the top and bottom of the signal should cover 4 vertical grids. I manage to calibrate a probe on Channel 1 without any problem. With the same settings and the same probe on Channel 2 the signal only spans half that (i.e. 2 vertical grids). Is this normal settings? If not how do I align the Channel 2 Volt/Div sensitivity to that of Channel 1. The manual doesn't appear to touch on that.
2. On the 1MHz signal, the rising and falling vertical side of the square wave is rounded but the probes doesn't have any R Trimmers to allow this to be adjusted. What does this translate to in practice.
3. On 1 occasion the rising and falling verticals of the square wave (during the 1MHz calibration process) appear to be missing. Is this something to worry about?
Many thanks
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1. The probe compensation process in the Hameg involves setting the Voltage/Div to 5mv/DIv and the Time/Div to 0.2ms/Div for the 1kHz square wave signal generated by the scope's internal generator. At these settings the top and bottom of the signal should cover 4 vertical grids. I manage to calibrate a probe on Channel 1 without any problem. With the same settings and the same probe on Channel 2 the signal only spans half that (i.e. 2 vertical grids). Is this normal settings? If not how do I align the Channel 2 Volt/Div sensitivity to that of Channel 1. The manual doesn't appear to touch on that.
It should be the same for the second channel. Please check several voltages (lab PSU or batteries) with both channels. Is channel 2 still off by factor two? Just for a specific Volt/Div or for multiple?
2. On the 1MHz signal, the rising and falling vertical side of the square wave is rounded but the probes doesn't have any R Trimmers to allow this to be adjusted. What does this translate to in practice.
It means that you should keep that in mind when looking at signals above 1MHz, i.e. the probe will suppress nice edges. Or that you should get some probes with low and high frequency adjustments ;-)
3. On 1 occasion the rising and falling verticals of the square wave (during the 1MHz calibration process) appear to be missing. Is this something to worry about?
If that happens again change the Time/Div to a lower value to get more waveforms on the screen. If the rising/falling edges are still not visible try to increase the brightness, sometimes the beam is too week to show them. And don't forget to check the trigger settings.