################################################ #To Do ####################### High priority issues that weren't yet addressed: 1. Capacitor physics issues. 2. Current chart shows inconsistent sign of current. 3. Performance issues on some machines. Top taskbar is covered up on windows. >>Should I do anything about this? Code is to maximize to visible screen area (discluding taskbars) for <=768 screen height, >>otherwise center at the top of the screen, leaving 100 pixels at the bottom. Fixed: When dragging a junction in a connected circuit, there becomes a gap in the electron flow 2 components away. >>My fix has the effect of holding the electrons still while dragging a junction. >>I could make them continue to flow with constant density with a bit more work, but not sure it's worth it. Solution for "Fixed: When adjusting a voltage or resistance continuously with a slider, the circuit doesn't update until stopped dragging." includes a non-elegant hack; not sure of an elegant way to solve this problem. "Advanced" controls should be show/hide, not enable/disable When Steve used CCK in class yesterday, some students interpreted the "Disable" button in the advanced section as "disabling" or "turning off" wire resistivity. This is a reasonable, but wrong interpretation, and it might be better to change the button from "enable/disable" to "show/hide" to avoid this confusion in the future. Voltage chart reads wrong value after switching sizes Chart tips don't move, should move on resize Inductor & capacitor incorrectly readout ohms, not Henries & Farads Change in AC Frequency shows readout for voltage. Noncontact ammeter doesn't update its reading when wire resistivity changes. He had a circuit partially built, then tried to undo something by reflexively hitting Ctrl-Z. His circuit dissappear, and was replaced by a battery and a resistor with electrons flowing in both directions through them. I tested this on my PC, and the same thing happened. This test behaviour should be taken out. He would like to be able to reduce the number of significant figures in the ammeter so that the resistance in the wires doesn't keep the numbers from looking perfect when he constructs simple circuits. He said that when he first builds a simple parallel circuit, he would like the currents to look exactly the same in both branches. With three decimal places, they don't, and he has to explain it at a time when he'd rather not. Get the time units to work out correctly. o Is the ac current (in a circuit with capacitor) symmetric? o If not, is the asymmetry correct? -When you have an AC voltage source and a light bulb in series and turn the frequency to 10 Hz, it looks like the current drifts slightly (counter clockwise) as it oscillates back and forth. I put the mouse cursor next to one of the blue dots and watched how one particular blue dot moves over time. Every 10 secs or so, the current stutters ever so slightly and shifts the current over. This seems like a very small/minor problem, but I'm not sure if it's effects can be easily seen with a more complicated circuit. -When I have 2 caps in series with a bulb and battery and turned the voltage up rather high, only one of the caps catches on fire (the one near the battery). See cck_fire.gif. >>Couldn't reproduce this yet. -There's a slight issues with the capacitors. I charged up two identical capacitor at different voltages (100 V and 10 V) so that there are different amounts of charges on them. Then, I removed the charged caps from their circuits (see cck_caps_separate.gif). I connected the positive side of one cap to the negative side of the other cap. I expected to see the charges on these two connected plates redistribute themselves, but nothing happened. (see cck_caps_together.gif). When you connect the outside plates of this 2 cap combo with some wires, the charges on the plates then properly distribute themselves. >>Yes, this is a real problem I'm not sure is addressed by my circuit analysis. I'm not sure whether my circuit analysis should be giving the right behavior here, or if we'll have to detect it and handle it separately. -On that same note, when I had 2 independent charged capacitors (not attached to anything else) it was sometimes hard to grab them with the cursor and move them. When you click on them, they would not be highlighted in yellow like usual. - Unfortunately performance is an issue ... it's pretty easy to get to the point where the mouse isn't working well and it is frustrating to build anything... is there any hope of improving this (ever)??? -I noticed the same performance issues as Kathy. As soon as there were many components in the play area, things got bogged down. Is this fixed in the piccolo version? - is there any way to make the current graph smoother? Right now it shows features that aren't really there? What should happen to the charge stored on a capacitor while the user is editing the capacitance? - Changing capacitance still doesn't show the right thing ... it doesn't show the electrons flowing again to fill up the plate with more or less charge. >>Yes, I thought it would be awkward to keep the charge constant across the capacitor while editing the capicatance (which would be implemented by manipulating the potential drop to account for the difference). The potential drop is constantly changing, based on other elements in the circuit, and I'm not sure of a good way to account for both of these issues. - I ran across a weird bug, (see attached). I had a nice looking circuit and when I was trying to add a bulb to it, it was sort of bogging down as I was dragging the bulb, and then all of a sudden it collapsed to one line, as shown and totally changed the components in the circuit (?). Do you have a short cut of keys that I may have pushed? >>I hope this problem will disappear when CCK is moved to piccolo. Has this problem disappeared in the piccolo rewrite? > We found a bug in AC cck. See the attached screenshot. To reproduce > it, hook up the circuit so it's all attached in a circle, then split the > junction that's shown split in the screenshot. See screenshot in email. There is something I noticed a while ago and forgot to mention. On CCK there is a clear button and it’s in a tool cluster labeled ‘File’; however, it’s job is that of reset and brings the sim back to it’s initial setup. Can you call it reset and move it out of that tool cluster? It came up today because it caused confusion for an individual using it in the booth. >>Asking for clarification. Circuit does fit better. I’m not crazy about requiring labels on all these clusters however on Advanced, it is necessary unless you replace Enable with Advanced. Deleting these cluster titles may be especially helpful in AC CCK if you’re running out of room. What do you think? Retitle the top tool cluster from "File" to "Circuit" in the control panel. Froze at Merlot talk. Bug report from McKagan: open circuit still conducts in particular situations • There is still a visible voltage drop across a plain wire, this should be removed. ################################################ #New Features ####################### See faraday's AC source graphics? Quantitative graph values. Quantitative CCK can wait until after AAPT - graphs ... would be nice to add dashed grid in background so easier to read where you are, also would be nice to have a cursor which could move around and scroll along graph, this would require a play, pause, step button to be added in bottom of sim. • Graph controls (quantitative) o Cursor o Readout While working on the interview paper Carl thought of a possible addition to CCK. What do you think about adding a person who can be used to test out the physiological responses to electricity. I’m not sure of the easiest way but he would have various reactions according the the stimulous. If it were as simple as touching a battery to his tongue (maybe to hard to integrate into CCK) he’d just jump a little and say something appropriate, as the shock gets stronger he may say ouch and finally it might just turn into a pile of black ashes or something. Problems to think about are making it too much fun and CCK is already very full. Possibly put him in the advanced panel. We came up with this because one of the benefits of simulations is being able to take risks without negative consequences and when students study electricity this is one of the most engaging topics and in lab students are quite often afraid of electrocuting themselves. What do you think? ################################################ #Lower Priority ####################### Help button should be moved south. o Improve the approximation for determining capacitor current. -Could use solution from companion model, but more difficult to code. There is a noticeable delay when dragging a component from the toolbox for the first time; this has confused some users. Bug: capacitor clips are clipping all electrons, not just electrons in that branch of the circuit Explain and remove fudge factor for capacitor in MNASolution? -If you build a simple circuit (battery, resistor, capacitor, and wires in series) and wiggle an element or node back and forth around with the mouse, the blue balls stop flowing from a node 2 or 3 nodes clock-wise from the element or node you are moving around. The blue balls stop flowing through this particular node, but the rest keep on flowing, so you get a wire or element with an absence of blue balls because they all flow out. This may be due to the fact that the wire has to redraw the number of blue balls because wiggling an element or node changes the number of blue balls (according to its length). o Set node voltages from the MNA, then use that to compute voltmeter readouts (instead of complex and error-prone graph theory computation). Quantitative numerical tests for RC, RLC Circuits, etc. -When there were two circuits running in the play area, there was definitely a decrease in performance and things ran a bit slower. If you grab a wire, say, from the tool bar and drag it around in the play area, there is a noticeable lag between the cursor and the wire moving with it. -When you have 2 caps in the play area and you turn one of them 180 degrees around, it looks a little strange next to the other one that has not been turned around--sort of an MC Escher effect. See cck_escher.gif.