What Causes the Amplitude Increase on an Oscilloscope When Touching the Lead?

  • Thread starter Thread starter nietzsche
  • Start date Start date
AI Thread Summary
Touching the oscilloscope lead increases the amplitude of the displayed wave due to the body's interaction with electromagnetic signals in the environment, typically at 50 Hz or 60 Hz from electrical outlets. The body acts as an antenna, picking up these signals and transferring them to the oscilloscope. This phenomenon highlights the oscilloscope's ability to detect voltage changes, even from invisible sources. The resulting wave displayed is a representation of these captured signals. Understanding this interaction can clarify the oscilloscope's function and the nature of the signals it detects.
nietzsche
Messages
185
Reaction score
0
Hi PF, it's been a long time since I've posted on here. I have a lab due soon and it was regarding oscilloscopes. This isn't really a homework problem so I'm not using the template...

Anyways, when I held the input lead in my hand, the amplitude of the wave displayed on the screen got much larger. I can't think of a reason why that would be. TBH, I still don't fully understand the concept of the oscilloscope. I understand that it detects voltage and graphs it as a function of time. But where is this mysterious voltage coming from when I touch the lead? And why is it even a wave?

Thanks in advance for your help.
 
Physics news on Phys.org
You are surrounded by electromagnetic signals (at either 50 Hz or 60 Hz), due to the electricity powering the outlets in the room you are in.

Your body acts like an antenna for these signals. By touching the oscilloscope lead, this signal is displayed on the oscilloscope.
 
Thanks Redbelly. I suspected it had to do with some antenna affect. It's still confusing though... it's so hard for me to understand things when they're invisible.
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Thread 'Egg Drop Challenge! Need ideas for winning designs'

I was thinking using 2 purple mattress samples, and taping them together, I do want other ideas though, the main guidelines are; Must have a volume LESS than 1600 cubic centimeters, and CAN'T exceed 25 cm in ANY direction. Must be LESS than 1 kg. NO parachutes. NO glue or Tape can touch the egg. MUST be able to take egg out in less than 1 minute. Grade A large eggs will be used.
View full post »

Similar threads

Understanding Oscilloscopes: How Can We Use Them to Measure RC Circuits?
Replies
4
Views
7K
Signal Generator, Oscilloscope and Capacitor
Replies
4
Views
1K
When can we use Vpp in calculations involving Ohm's law?
Replies
2
Views
3K
What is the Speed of Sound in this Lab Setup?
Replies
1
Views
3K
Regarding calculation of sound wavelenth
Replies
4
Views
3K
I Mechanism of Energy Conservation in Zero-Amplitude Sum of EM Waveforms
Replies
12
Views
689
What Causes Frequency and Amplitude Instability in Oscillating Crystals?
Replies
3
Views
2K
What Causes the Waveforms When Holding an Oscilloscope Probe?
Replies
2
Views
4K
When using a DMM to check for a short to ground, why do you need one lead on ground?
Replies
16
Views
5K
Significant figures when taking measurements.
Replies
5
Views
6K

Hot Threads

Recent Insights

Back
Top