Quiz Images: LR Circuit Scopes

 Here is another set of quiz images. This week's theme is resistor-inductor circuits.

This is a set of output voltage responses superimposed on the applied voltage (e.g. signal and response). The applied voltage (signal) is always shown as oriented "up": it is a square wave of 2.0 V amplitude and 2.0 V DC offset. The "response" is the voltage (vs time) across either the inductor or the resistor in the LR circuit, and the probe polarization may be the same or the opposite of the applied voltage polarization.

A couple of circuits connected in combination.

What changed to make the response to this signal change as shown above?

Here is a signal and response with some numbers around the half-life and quarter-life decay. This is an LR circuit using a ~6.8 mH inductor with a total resistance of about 200 Ω. The sampling rate means that these times are only approximate, unfortunately. I have several more images like these, with the same stipulation concerning sampling rates.

Same as previous, but with maybe a slightly better sampling rate, and the total resistance of the inductor + added resistor is now only 100Ω.

Here I replaced the pasco resistor-capacitor-inductor circuit board with and actual inductor. The nominal inductance is 63 mH, which is about an order of magnitude larger. Again, I kept the total resistance (internal for inductor + additional resistor box) to about 100 Ω. I should probably mention that for all of these, the voltage probe is looking only at the voltage drop across the added resistor. 

These two are for the same solenoid, but I have increased the total resistance (internal + added resistor) to 200Ω. I placed them here side-by side (or above and below) so that you can get a sense of the uncertainty in measurement: these are the same signal trace, I just moved the cursors to their nearest-neighbor positions.