Hi everyone,
I know that I double posts of measuring mains AC, but to be clear I'd like to summarize all options.
First of all, my equipment: RIGOL 1054Z. standard probes CATII 300V
My main AC: 230V 50Hz (at least should be), and at home I have system of two wires L + PEN (TN-C), PEN wire is split in my basement to PE (go to ground), N (go to main grid).
And sockets in walls have three pins plug (see picture below) where PEN wire is connected to right hole and ground pin.
Reason of measuring AC:
- Measuring my mains grid AC - I have some trouble with my grid (when I'm using computer or 3D printer lights blinking).
- Another reason is to measure how triacs work - I have now some mini project with four triacs which control 1kW heaters each and sometimes, after few hours control unit stops and on LCD I see different signs (like Chinease signs), I control them with different time on/off, longer then 2sek ON (no phase control).
=>For this reasons and for me own safety I'd like to know all posibilites to measure such things.
For now:
- I watched Dave EEVblog yt movie "How not to blow up your osciloscope"
- "Oscilloscope operation differential voltage measurement"
- and many other movies about measuring voltage.
Options:
a) I can buy new probes with higher voltage resistant => CAT II 600V DC + peak AC (230V * square root (2) = 325V, much lower than permisible probes max voltage). and not use ground probes wire
+ cheap - 15-25$/probe,
- not grounded oscilloscope
- I can only measure difference between point and ground.
b) Differential measuring - use two channels and plug ground wires of probes together.
- I need new probes as in point 1. but cheap
- not grounded oscilloscope
- I can measure difference between two point - as like between transistor or triac - drop voltage.
c) I can use isolation transformer.
+ I can measure any point of my circuit -
- more expensive then new probes CAT II 600V.
- when I want measure my main AC there is not a problem - I can buy smole power transformer. Bigger probles is when I want to power up my heater in my project where I have over 4kW of power - it is too expensive for me now.
d) insolated differential probes or new oscilloscope with insolated channels
- more expensive then insolated transformer but too expensive for me now
+ most safety solution
Questions:
1. When I use isolation transformer (1:1) and I have some speakers in input AC, the waveform will be different at input and output? Output waveform will be more smooth?
2. In option C) (isolation transformer), can I plug ground wire of probes to one any wire of transformer output - differential measure? When I've insolation transformer ground or positive wire of probes can be pluged into any points of circuit?
I would like to start from buying new probes (1:10 CATII 600V or higher) and test my mains AC directly - no isolation transformer and without pluged ground wire of probes to anything.
Then set up differential measurement with my RIGOL 1054Z and two new probes and test triacs.
Could you tell me is in this connetion some problem?? (I know that this is on my own risk of injury my self, but I want to avoid to burn out something - oscilloscope or some fuses at home).