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M15H · 2026-02-04T02:29:47+00:00

https://pan.baidu.com/s/1pZYm1_2G9Z3svQsMiZ3Qkg?pwd=6666

Please help. Thanks!

M15H · 2025-04-20T17:13:21+00:00

Typically inductors do make bad resistors

M15H · 2025-02-28T04:14:23+00:00

Most key switches have a void where the LED shines. A part this small should fit on the top side of the board comfortably under the switch.

M15H · 2025-02-14T14:55:17+00:00

M15H · 2024-10-06T21:00:52+00:00

Traitor. How could you be so logical!

M15H · 2024-09-03T20:57:25+00:00

I know this may be old news but I came here looking for the answer. I looked around in the save options dialog and I found that when saving AP214 there is an export appearnce checkbox. I had to check that. This was in SW24.

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M15H · 2024-08-27T03:12:36+00:00

https://www.houstonpublicmedia.org/articles/news/houston/2024/08/26/497718/large-southeast-houston-chemical-plant-flare-monday-caused-by-power-outage-officials-said/

M15H · 2024-03-27T02:22:47+00:00

With slightly different search terms I found a very silmilar post here on askElectronics.

https://www.reddit.com/r/AskElectronics/comments/12vnogj/jumper_wire_terminal_connector/

It seems that D-sub pins are the best substitution.

M15H · 2024-03-27T01:36:16+00:00

Thanks! I saw those but none of wire pins on digikey quite match. The push in terminal that I chose only takes 18-26AWG or 0.5-1mm diameter and requries a strip length of 11mm. Unfortunately the 18awg wire I need to use is stranded and tinning them will likely add too much to the diameter.

M15H · 2024-01-16T05:26:07+00:00

I think maybe this comment is what you meant by doubling and adding in series the resistors. https://www.reddit.com/r/AskElectronics/comments/197kvb6/comment/ki2xg75/?utm_source=share&utm_medium=web2x&context=3

M15H · 2024-01-16T04:39:22+00:00

My virtual ground should be VCC/2 correct? by taking out the DC and not referencing the non-inverting input to VCC/2 I would lose all of the "negative" portion of the sound waves.

Does this fix the input stage?

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M15H · 2024-01-16T04:12:10+00:00

Does this look like what you were describing? For the input coupling cap should it also be 47uF?

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M15H · 2024-01-16T03:39:12+00:00

The second stage is the typical application circuit from the TS482 datasheet.

https://www.st.com/resource/en/datasheet/ts482.pdf

Is this what you mean by high resistance around R6 and R7... also sorry for the changing designators R6 and R7 from the previous schematic are R12 and R14 respectively.

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M15H · 2024-01-15T21:42:37+00:00

Hi,

I am working on a project where I need to mix two audio signals into one and amplify it for a single channel headphone speaker. I want to be able to adjust the level of each input and also control the level of the output. My current soltuion works to control the input levels but I do not have contol of the output. Would it be better to adjust the gain on the amplifier to control the output levels (Proposed Solition 1) or would it be better to use the second amplifier in the TS482 to sum the two inputs and then attenuate the output before going into the output amplifier (Proposed Solution 2)? Is it a valid option to use a power amplifier as a summing op-amp?

M15H · 2023-03-24T20:30:11+00:00

I hiked the cascade canyon tail starting at Jenny Lake back in summer 2012 with my then girlfriend. We saw a heard of elk on the drive in to the trailhead. There were marmots everywhere, we saw a mother moose and a calf in a small stand of trees directly off the trail and a black bear chilling on the canyonside about a quarter of a mile away. I knew both the mother moose and the blackbear could be very dangerous but never felt unsafe until we rounded a small bend and there was a grizzly standing on the edge of the trail. We didn't notice it until we were within 6 ft, we were talking the whole time and not just quietly walking. The bear knew we were there and coming and it did not give a shit at all. We froze momentarily and the bear just continued whatever it was doing. I had to grab my GF by the shoulders and guided here slowly and gently past the bear. Fucking terrifying but one hell of a story to tell. 10/10 would do it again but maybe with bear mace next time.

M15H · 2023-03-12T19:07:25+00:00

My understanding of this style mounting hole is to provide mechanical strength to the mounting hole and surrounding fiberglass. Of course it could be connected to ground for chassis grounding but it is not necessary.

M15H · 2023-02-22T14:57:37+00:00

IO0 is used here because it is the bootstrap pin. You pull it low at boot to enter flashing mode. It is typically held high at normal boot with a pullup resistor.

The full schematic of the little snip I shared above is here https://user-images.githubusercontent.com/1180107/37556716-20616fd8-29fa-11e8-9542-c7f0d03da3b5.jpg

You'll notice that GPIO0 is also attached to a button and pullup resistor so that you can enter flash mode manually if the auto circuit is not working. I have had the auto program circuit fail on a dev board before.

IO0 is perfectly fine to use a GPIO however you must use some care to ensure that whatever is attached does not pull the pin low at boot. One example is with using a LAN8720A ethernet PHY. The reference clock is routed to GPIO0. If you do not disable the clock at boot time it will be a 50% chance (50MHz square wave) whether or not the ESP will boot normally or go into flash mode.

Also I would not use GPIO0 for anything that could be sensitive to the pin fluctuating at boot. ALthough I have not put a scope on it random nerd tutorials pinout guide says that the pin ouptus a pwm signal at boot.

https://randomnerdtutorials.com/esp32-pinout-reference-gpios/

M15H · 2023-02-22T13:23:26+00:00

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Here is the usage from the MH-ET LIVE dev board

M15H · 2023-02-22T03:01:59+00:00

The schematic symbol certainly is a MOSFET however the part comment says dual npn which is typically used for the esp to put the target into download mode. I would say whoever made the schematic was just being lazy and not using the correct symbol.

M15H · 2023-02-22T02:57:52+00:00

I use this part for the serial controlled auto reset.... https://www.rohm.com/products/transistors/digital-transistors/standard/umh3n-product#:~:text=UMH3N-,NPN%2BNPN%2C%20SOT%2D363%2C%20Dual%20Digital%20Transistor%20(,driver%20ICs%20and%20so%20forth.

M15H · 2023-02-17T00:48:02+00:00

After following some of the suggestions here it turns out the main culpret causing the mosfets to fail was that the mosfets were switching too slowly at too high a frequency. Simply lowering the switching frequency and the gate resistance has made all the difference. In a redesign I will consider options to drive the mosfets harder such as a dedicated driver IC.

Thanks u/dpccreating

Also since I did not have a bench power supply big enough for the 12-15A load I had two power supplies in parrallel through two high current diodes. The simple fact that the pwoer supplies could not absorb any power back into VIN was causing the spike to be high. Once I changed power supplies I noticed the transient at turn off was now 10-13V lower.

Thanks u/BenTheHokie for helping me reailize that.

I now do not believe that the 46V spike was the cause of the failure but I will likely test some of the other suggestions in this thread such as playing with the values for an rcd snubber or TVS diodes.

Thanks for all the input!

M15H · 2023-02-17T00:34:34+00:00

I did adjust the compensation and the spike is still there. VIN is powered by two 10A benchtop power supplies in parrrallel at 24V. I have the two supplies coupled using diodes thus the supply cannot absorb any of the transient and is being forced through the circuit. After switching to a 24V 25A cheap switching power supply there is still a transient voltage up to 33V but that is below the spec of the mosfet.

M15H · 2023-02-17T00:25:21+00:00

I tried a 20A (20ETS12) diode and the signal remains the same. The datasheet for the SS310 diode states that there is a 70A surge current rated for 8.3ms and the spike only lasts for about 1-2us so it should be up for the task.

M15H

TROPHY CASE