The only oscilloscope I have is a tiny DSO138 (input section is on the top left of page 4 in the linked PDF). The scope has a limit of 100Vpp (actually displays only 80Vpp). At the highest attenuation (100x), there is 1V input to the first op-amp.
I want to see the output of a step down transformer. The transformer secondary shows 40V AC on my multimeter. Assuming this to be close to the RMS value, peak would be 56.5V and peak to peak at 113V. This is slightly higher than what I should put into the scope.
How can I go about attenuating the signal? Will a pair of 100K resistors as voltage divider work (with input set to 100x on the scope)? Will I need to attach any capacitors? I will probably never use it for more than 200Vpp ever, but there is an audio amplifier project coming up. If I can make a decent probe to view 100-200Vpp, it will be helpful.
All advice will be helpful. My electronics knowledge is rather limited (but I cannot go out and buy a proper probe or scope just yet). Also, I've never used a real scope.
Here is the input section of the scope:
edit: As far as I understood, standard scopes come with a 50Ohm and a 1M resistor inside them, and probes are 1x/10x/100x/1000x with reference to that, with 10x being most common. Is this XXXx multiplier with reference to the first op amp input voltage (somewhere around 0-1V)? That would mean my scope already has the 1x, 10x, and 100x probe circuits built in, right? Would that mean using an additional 10x passive divider give me grossly innacurate results? Are scopes mostly used for seeing waveforms in the 0-10V range?
Another question: The input opamp TL084 has a bias current of 30pA (max 200pA). With the input 100K on the lowest range, that would mean my lowest ranges are not protected upto 100Vpp. Only protected upto +=5V and +-50V, even though there is a 100K resistor on the input of the lowest range?