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Activity for Olin Lathrop‭

Type On... Excerpt Status Date
Edit Post #293120 Initial revision 4 days ago
Answer A: Is Feeding a Watchdog Timer from an ISR a Bad Practice?
Feeding the watchdog from an interrupt service routine is indeed a bad idea, usually. It depends on what you are really trying to protect against. The purpose of a hardware watchdog is usually to allow recovery if the processor stops doing what it's supposed to be doing. The question then become...
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4 days ago
Comment Post #293111 That's important information that should be in the question, not hidden here in a comment.
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4 days ago
Comment Post #293111 Are these results you are seeing from a simulation or an actual circuit? V5 might also be backwards depending on the answer. If a simulation, then it probably is putting out -2.5 V on its positive terminal. If a real power supply, then you wired it backwards since the negative output should be on ...
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5 days ago
Edit Post #293082 Initial revision 12 days ago
Answer A: Summing op-amp 10 meters long
Yes, that should work. Each sensor is then dumping a current related to its measurement onto a single common wire. Basically, the sensor outputs are summed because currents add. 10 m shouldn't be an issue for 1 kHz. The harder problem is avoiding external noise pickup. Make sure everything is ...
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12 days ago
Comment Post #279592 Unfortunately that is something the author needs to do. The links weren't to the image hosting part of Codidact, as they should have been.
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14 days ago
Edit Post #276217 Post edited:
18 days ago
Edit Post #293049 Post edited:
22 days ago
Edit Post #293049 Initial revision 22 days ago
Answer A: Ground loss protection
It all depends on what is connected between the main board and this "hat" board. Your schematic doesn't show any of these connections, so we can't really tell. In the end, the high current loop should be isolated from everything else. In your context, V3 would be an isolated supply. The circuit...
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22 days ago
Edit Post #293044 Initial revision 23 days ago
Answer A: OP-AMP PT100 signal conditioner
I'm going to guess that by "PT100" you mean a positive coefficient temperature sensor with a nominal resistance of 100 &Omega; at 0&deg;C or 25&deg;C. Whatever it is you mean, it should be in your question. This circuit has several independent parts, but that's hard to see at first glance due to ...
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23 days ago
Comment Post #293038 Define "PT100" and how you want to "condition" its signal.
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23 days ago
Edit Post #292999 Post edited:
29 days ago
Edit Post #292999 Initial revision 30 days ago
Answer A: Controlling the shutdown pin of an IR Transceiver
When the switch is ON the transceiver will be active No, it's the other way around. First, you should be able to see the bar over SHDN in the datasheet. That means negative logic, where low is asserted. Second, on page 5 of the datasheet the description for the SHDN pin is "Shutdown input. ...
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30 days ago
Edit Post #292938 Initial revision about 1 month ago
Answer A: Controlling the Low power mode of Buck Boost converter using a Microcontroller
Read the datasheet and do the math. On page 3 of the datasheet we find that the guaranteed high and low threshold voltages for the PS/SYNC input are 1.4 and 0.4 V, and its maximum input current is 100 nA. First, let's analyze your circuit letting the input float high. Your lowest power input v...
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about 1 month ago
Edit Post #292901 Initial revision about 2 months ago
Answer A: OPA2211 datasheet discrepancy
You are right in that the gain at 80 MHz is clearly not 100. Both the initial marketing points and the graph seem to agree on a gain&sdot;bandwidth of 45 MHz. There does appear to be a slight kink in the gain curve at 800 kHz, but it looks like the gain is a bit below 100 there. A gain of 100 at...
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about 2 months ago
Edit Post #292876 Initial revision about 2 months ago
Answer A: How does JFET biasing work in a 2-terminal electret condenser microphone?
The voltages from the raw microphone are quite small and fairly high impedance. That's why an amplifier at the mic is needed in the first place. The signal on the wire would be way too small compared to noise in normal environments. The FET is a simple amplifier that increases the voltage and decr...
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about 2 months ago
Edit Post #292791 Initial revision 2 months ago
Answer A: Opto-coupler, slow turn off
Some optos are really slow. What off time is yours specified for? Your circuit could be better. The transistor is turned on thru 1 k&Omega;, but off thru 11 k&Omega;. You are also giving it way more base current than needed, slowing turn-off. Move R318 to the other side of R317 and adjust bo...
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2 months ago
Comment Post #285392 It looks like those images weren't hosted on Codidact as they should have been. The third-party host apparently deleted them, or changed the URL. This is exactly why images shown here should be hosted here.
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3 months ago
Edit Post #292691 Initial revision 3 months ago
Answer A: Why did the battery blow out?
Those batteries must be for powering electronics that receives commands from your controller or remote. They don't have anywhere near the energy to raise something like the headrest of a normal bed. However, that has nothing to do with why one of them failed. I've never seen a 9 V battery fail l...
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3 months ago
Edit Post #292690 Initial revision 3 months ago
Answer A: Which transistor type to use for charge shuttle, as part of an active charging circuit?
You need something with very low on-state voltage drop. That effectively means some type of FET. Those look resistive when on, as opposed to a voltage source like a BJT does. You need to look carefully at the voltages when the switches are supposed to be off. The body diode of MOSFETs and the g...
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3 months ago
Comment Post #292541 The sine will be infinite in time, not voltage. I have edited the answer to make that clear. Also, a 1 V step input will result in less than 2 Vpp sine due to the two inductors acting like a divider.
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3 months ago
Edit Post #292541 Post edited:
3 months ago
Edit Post #292541 Initial revision 3 months ago
Answer A: Analysis of LC circuit using intuition
A quick intuitive way of looking at this circuit is that the voltage source, L1, and L2 can be thought of as a lower voltage source with a single lower inductance in series. This is the same as finding the Thevenin equivalent if L1 and L2 were just resistors. Put another way, L1 and L2 are in paral...
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3 months ago
Edit Post #292527 Initial revision 3 months ago
Answer A: Connector rated voltage vs IPC-2221B and IEC 62368
If I use this connector at its rated working voltage, does that automatically mean I am not complying to IEC 62368 safety standard? The pattern you reference seems to assume one side of all eight signals are tied together. If that is really true, then I don't see how to interpret working voltage ...
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3 months ago
Edit Post #292496 Initial revision 4 months ago
Answer A: Issue in Cable Sizing and control cable selection
200 HP is 147.1 kW. At 480 V, it takes 306 A to transfer that much power. You didn't say, but your 480 V power feed is probably three-phase, and the motor is three-phase too. I don't remember how exactly that reduces the current requirements in each of the three conductors, so let's just say you...
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4 months ago
Comment Post #292378 Explain in a few sentences what the software you are looking for is supposed to do. "PCB modeling" is too vague. Links rot over time, and go to unknown places. Information required to understand the question must be in the question itself. Links are OK only for supplemental information.
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4 months ago
Edit Post #292309 Initial revision 4 months ago
Answer A: Do hobbyist slabtop Wi-Fi modifications need to consult FCC regulations?
is it possible that moving around laptop antennas does not change the specifications drastically, because, for example, the antennas are low-power The radiated power is probably not low compared to what is allowed. Laptops with limited WiFi range don't sell well. The limit could also be in the...
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4 months ago
Comment Post #292235 Clicking on that link goes to a page that pops up something about permissions. No thanks. Not going to look further. Please provide a proper link.
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4 months ago
Edit Post #292148 Initial revision 5 months ago
Answer A: Purpose of resistance between SENSE/FORCE line of power supply
I see that Nick has already provided a good answer to R5, so I'll only address this: Furthermore, an amplifier symbol called "gm" is labeled as transconductor. What does it do? What you show is a rough diagram only intended to give enough insight into the internal workings to use the power supp...
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5 months ago
Edit Post #292090 Post edited:
5 months ago
Edit Post #292090 Initial revision 5 months ago
Answer A: Circuit for earth conductor presence detection
The section you quoted says: "by injecting a small amount of current into the ground". With a solid ground connection, the voltage on their ground pin shouldn't change no matter what current is injected onto it. If they inject a current and see a resulting voltage change, then they know the groun...
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5 months ago
Edit Post #292089 Initial revision 5 months ago
Answer A: CAN bus open circuit detection
There is no direct way to determine whether the PIC is connected to a CAN bus. Part of the problem is that the PIC never directly connected to the CAN bus anyway. There is a transceiver chip like the MCP2551 between the PIC and the bus. The PIC interfaces to the transceiver via two digital signals...
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5 months ago
Edit Post #291984 Initial revision 5 months ago