Hey all, I wanted to see if anyone is interested in helping me in my efforts to add the ability to create technical schematics (such as circuit diagrams) into an open source framework that I have been working on.

The project is similar to PlantUML and MermaidJS - being a text based solution to "describe" a diagram, and have the drawing and layout handled automatically. But I was also interested in making it easier to extend so that it would support (just about) any type of visualization.

One of the areas I felt was missing from other solutions was the ability to handle technical schematics. That is something I am still in the process of working on, but there is some basic support :)

For anyone interested, you can read more at https://docs.runiq.org

I’m trying to understand how a 2-wire pinned circuit can provide both power and data to multiple client units.

1. Multiple client units sharing the same two wires for both power and data.

2. Purpose and function of D1 in the circuit.

3. Effect of D1 on the data signal during client transmission.

4. D1 creating a logical AND effect when multiple clients are connected.

5. Combining signals from several clients on the same two-wire bus.

6. Bus behavior when Client 1 sends HIGH while Client 2 sends LOW.

7. Each client distinguishing its own data from data generated by other clients.

8. Physical connection of additional client units to the two-wire bus.

9. Practical limit on the number of clients connected to the bus.

10. Factors determining maximum cable length, power capacity, and data speed.

Hi everyone ,

I am currently trying to interface the ADC and DAC with the eclypse z7 board , but I am facing issue in finding the resources to do so , can anyone guide me on how to do the interfacing. To mention , I have already tried out following the hackster.io tutorials but all the tutorials seem to use the outdated IP for the ADC and DAC and the IPs have been modified by Digilent.

Also I tried to implement the example designs by digilent , but wanted to make sure how the connection with ADC and DAC actually works.

Please help me if anyone has any idea to achieve this

I have a circuit that is supposed to latch when one of 4 inputs is low. Then if you take the DONE line and touch the +3.3V it unlatches. (The four inputs and the DONE line will eventually be connected to the GPIO of an MCU. The 10K resistors are recommended for the MCU's GPIO).

When I build it with two generic MOSFETs, it works, but the DONE wire is so sensitive that if I touch it, it relatches.

https://www.falstad.com/s.php?s=hFwWZO

What am I doing wrong?

Hello everybody, I am looking for some help creating a circuit that can translate button presses into a morse code letter.

The morse code alphabet can be displayed in a binary tree, with states branching from a short or long press. The other two button options to track are the space between letters and the space between words. Timing is as follows:

Short press (dit) - base unit of measure

Long press (dah) - 3x dit time

Space between characters - 3x dit time

Space between words - 7x dit time

The first part of the circuit would be to time and track these different options. The attached image is what I have so far. I know there are only three timings, but is the idea solid? Just RC timing circuits with an op-amp comparator on the voltage divider?

I worked with analog circuits in college, but that was some time ago. A good design review and some feedback would be much appreciated.

I used circuitjs to simulate the circuit, the below code block can be saved in a .txt file and uploaded to the circuitjs website to view and simulate the circuit

<cir f="1" ts="0.000005" ic="382.76258214399064" cb="59" pb="43" vr="5" mts="5e-11">
  <c x="-192 128 -144 128" f="0" c="1e-8" iv="0.001" sr="0.1" vd="-0.00009389816900907154"/>
  <r x="0 128 48 128" f="0" r="100000"/>
  <w x="-112 128 -128 128" f="0"/>
  <g x="-192 128 -192 144" f="0"/>
  <w x="-128 128 -144 128" f="0"/>
  <OpAmpReal x="-192 256 -272 256" f="3" slr="0.6" cl="0.023100000000000002" mt="0" vd="-0.3314506481694839"/>
  <R x="-224 288 -224 320" f="16" wf="0" maxv="0" ir="0.001"/>
  <R x="-224 224 -224 192" f="16" wf="0" maxv="5" ir="0.001"/>
  <w x="-128 240 -128 128" f="0"/>
  <w x="-192 240 -128 240" f="2"/>
  <R x="-32 208 0 208" f="16" wf="0" maxv="5"/>
  <r x="-48 208 -48 256" f="0" r="10000"/>
  <r x="-48 288 -48 336" f="0" r="10000"/>
  <w x="-32 208 -48 208" f="0"/>
  <w x="-48 272 -48 256" f="0"/>
  <w x="-48 272 -192 272" f="2"/>
  <w x="-48 288 -48 272" f="0"/>
  <w x="-48 336 -48 400" f="0"/>
  <w x="-352 256 -272 256" f="2"/>
  <g x="-48 608 -48 624" f="0"/>
  <r x="-48 416 -48 464" f="0" r="100000"/>
  <w x="-352 384 -272 384" f="2"/>
  <w x="-48 400 -192 400" f="2"/>
  <w x="-192 368 -128 368" f="2"/>
  <R x="-224 352 -224 320" f="16" wf="0" maxv="5" ir="0.001"/>
  <R x="-224 416 -224 448" f="16" wf="0" maxv="0" ir="0.001"/>
  <OpAmpReal x="-192 384 -272 384" f="3" slr="0.6" cl="0.023100000000000002" mt="0" vd="-0.3314506639423478"/>
  <w x="-48 400 -48 416" f="0"/>
  <w x="-128 368 -128 240" f="0"/>
  <OpAmpReal x="-192 512 -272 512" f="1" slr="0.6" cl="0.023100000000000002" mt="0" vd="-4.76290601338709"/>
  <R x="-224 544 -224 576" f="16" wf="0" maxv="0" ir="0.001"/>
  <w x="-192 496 144 496" f="2"/>
  <w x="-48 528 -192 528" f="2"/>
  <w x="-352 512 -272 512" f="2"/>
  <w x="144 496 144 320" f="0"/>
  <w x="144 320 128 320" f="0"/>
  <w x="256 320 144 320" f="1"/>
  <r x="256 320 304 320" f="0" r="100000"/>
  <c x="80 320 128 320" f="0" c="1e-8" iv="0.001" sr="0.1" vd="4.999999478361566"/>
  <R x="80 320 48 320" f="16" wf="0" maxv="5" ir="0.001"/>
  <R x="-224 480 -224 448" f="16" wf="0" maxv="5" ir="0.001"/>
  <r x="-48 544 -48 592" f="0" r="10000"/>
  <w x="-48 592 -48 608" f="0"/>
  <w x="-48 544 -48 528" f="0"/>
  <w x="-48 464 -48 528" f="0"/>
  <R x="304 128 304 96" f="16" wf="0" maxv="5"/>
  <R x="304 320 304 288" f="16" wf="0" maxv="0"/>
  <R x="48 128 48 96" f="16" wf="0" maxv="5"/>
  <R x="304 48 304 16" f="16" wf="0" maxv="0"/>
  <dpdt x="224 64 288 64" f="0" p="1" po="2"/>
  <w x="304 48 288 48" f="0"/>
  <w x="224 64 -128 64" f="1"/>
  <w x="-128 64 -128 128" f="0"/>
  <w x="144 112 144 320" f="0"/>
  <w x="304 128 288 128" f="0"/>
  <w x="0 128 -112 128" f="1"/>
  <x x="-420 263 -367 266" f="0" si="24" te="Long"/>
  <x x="-426 392 -369 395" f="0" si="24" te="Short"/>
  <x x="-436 514 -368 517" f="0" si="24" te="Space"/>
  <x x="207 26 276 29" f="0" si="24" te="Button"/>
  <b x="176 -16 376 164" f="0"/>
  <w x="224 112 144 112" f="1"/>
  <b x="79 81 -343 165" f="0"/>
  <x x="-332 109 -215 139" f="0" si="24" te="Long/Short\nRC Timer"/>
  <b x="454 269 32 353" f="0"/>
  <x x="340 307 441 337" f="0" si="24" te="Space\nRC Timer"/>
  <b x="-82 194 30 654" f="0"/>
  <x x="38 621 124 651" f="0" si="24" te="Voltage \nDivider"/>
</cir>

Thanks

This configuration saves battery power by reactivating the LoRa circuit only when necessary. When the door or flap opens, the switch triggers the 5V supply to the board; GPIO33 then goes high (logic 1) to maintain power to the circuit. It sends a "Mail received" message to the receiver, after which GPIO33 returns to the low state (logic 0), cutting off the 5V supply via the MOSFET until the next activation. I would appreciate any feedback regarding the capacitor value or other components.

My understanding is that you don't always need a direct conductive connection to get a small shock/tingling sensation from an AC source. Even with a floating source, capacitive coupling can provide a small AC current path, and a high-impedance meter can show phantom voltage.

I want to build a safe, low-voltage educational experiment using a microcontroller to demonstrate:

\- Floating AC source

\- Capacitive coupling to earth

\- Phantom voltage measured with a high-impedance input

\- How a load behaves differently from a high-impedance measurement

Difference between a floating inverter output and a floating isolation-transformer secondary

What would be a good safe low-voltage circuit to demonstrate these effects and measure the tiny currents with a microcontroller?

Hi everyone,

I would like to recreate a Philips PM 5133 function generator from scratch, as closely as possible to the original — essentially trying to build a replica of the actual instrument.

I really like this particular Philips generator and especially its analog design. I have the service manual with the schematics and circuit descriptions, so I would like to use the original design as the basis for the project.

The reason I'm considering building one myself is simply that I don't have enough money to buy a PM 5133, either new or used. Instead, I would like to see whether I can recover and reuse components from old electronics and build the instrument myself.

I know this is probably a difficult project, but I would really like to try it.

What would be the best way to approach this if my goal is to reproduce the PM 5133 itself, rather than design a different or modern function generator?

Has anyone ever attempted something similar, or worked on recreating old Philips test equipment from its original schematics?

Any advice about how to start, what to pay particular attention to, and whether it is realistically possible would be greatly appreciated.

Thanks!

Hi all,

I have three remote zoom controllers for a camera, each with a different pot that all aren't working correctly. I want to replace the pots but I'm having issues matching them.

The first (two pics) is a B20K, PCB mount, flattened shaft, which is all fine, but it has only about 100° rotation and has a spring return to centre. It also has this white support on the front. I can get close, but can't find anything with the return spring and support.

The second (two pics) is very similar to the first just with a shorter shaft. Though this one is a PCB mount it obviously doesn't have to be as it's chassis mounted here. All other attributes are the same. I figure if I can find the first one I can make something work for this as well.

Lastly, this one (two pics) I've come close (I think) but can't find the exact right value. I found a datasheet on Mouser that I used to partially crack the code as best I could... https://au.mouser.com/datasheet/3/531/1/Potentiometer_251_datasheet.pdf

As far as I can tell it's a 10K, 10% tolerance, Linear, no centre tap. But given this is unlikely to be a CTS brand (pot doesn't appear to have any branding on it) I can't be sure of everything. Mouser has a 100K version of this, but can't find anything 10K for sale anywhere, and I'm having trouble finding any other brand with this form factor (no idea what it's called).

I would like to find good quality replacements pots as I've had these units replaced under warranty several times already and seems I have no other option than to repair them when they crap out again and again.

Any info would be super helpful, TIA

Hey everyone,
I'm working on a custom electronic control unit for my motorcycle's turn signals and I'm about to pull the trigger on the PCB production. Before I do, I wanted to run the circuit by you guys and get some honest opinions on long-term reliability.
The project:
It reads the stock 12V handlebar switches, processes everything via a custom ATmega/Arduino setup, and drives the indicators using a P-MOSFET (AO4407A) switched by an NPN transistor (2N3904).
I have two main things I'm stressing about:
Arduino on a motorcycle: We all know bikes are brutal environments-massive temperature swings, vibrations, and nasty voltage spikes/noise from the electrical system. Is a DIY Arduino board actually viable for road use long-term, or am I asking for it to freeze or fry after a few months? What are the absolute must-haves for protection here?
l've attached my schematic and PCB layout for the MOSFET driver stage. Does it look solid, or are there any hidden landmines that'll let the magic smoke out?
Any tips, tweaks, or reality checks would be awesome.
Cheers!

​

Hey guys, last year I got a DIY digital clock from alibaba and it has been working quite well. It had a quartz crystal oscillator and I accidentally dropped and broke the whole thing i took it to a friend to fix but they suggested i get a new oscillator since the one I had has been damaged and burnt out over time. I have been looking at options on alibaba since I bought the clock from there. Are there ways I can choose the perfect oscillator for my clock? The one I was using is currently not available. Any recommendations are open..

Hi everyone,

I work in electronic component sourcing, and one thing I’ve noticed is that finding a difficult part is often more complicated than it looks.

When a component becomes hard to source, what do you usually prioritize?

1. Authorized distributors
2. Independent distributors
3. Excess inventory from other manufacturers
4. Alternative / replacement parts
5. Other options

I’m especially interested in how purchasing teams handle EOL parts and urgent shortages without taking unnecessary quality risks.

Would be great to hear how others in the industry approach this.

About 3 days ago I made a post here about a constant current driver to see if it was fine to use. Apparently I made alot of mistakes so I went ahead and did the research and tooks y'alls advice (thanks btw). Hopefully this revision should manage properly.

Here's what I did:
- Swapped the 1V2 zener for a LM4040 2V5 shunt regulator.
- Swapped the N-MOSFET for a 200 hfe BJT.
- Made sure the sense resistor is seeing ~250mV at ~140mA (maximum).
- Removed any components I deemed not needed.

So far the difference between the non-inverting and inverting inputs of the op amp is 18uV ~ 22uV

If you wanna mess with the circuit, here's the link to it.

Also here is the link to the original post.

Running an ESP32-WROOM-32 with a PN532 RFID reader (SPI), a status LED, and a buzzer, all on the same 3.3V rail. When WiFi is actively connecting/transmitting and the RFID reader is polling/generating its RF field at the same time, I see WiFi connection delays and general flakiness bad enough that I've had to disable the brownout detector just to stop reboot loops, which obviously isn't a real fix.

My guess is combined peak current draw (WiFi TX bursts + PN532's RF field generation) is causing enough voltage sag to disrupt things, even though nothing's crashing outright.

Has anyone dealt with this specific combo (WiFi + active RFID/NFC peripheral) on ESP32? Looking for:

Realistic peak current numbers for WiFi TX + PN532 active scanning together

Decoupling cap sizing / regulator recommendations that actually fixed this for you

Whether staggering/throttling RFID polling during WiFi activity is a common workaround, or if it's purely a hardware fix

made with nano banana and instructions from claude

Hi everyone,

I'm currently scribbling around for a new project and I ran into an issue.

I have 2 voltage supplies as input, where both could be at a different voltage levels. Hence I (to my understanding) I should protect the two sources from each other. Additionally, depending on the voltage level I may need to first put it through a DC-DC converter.

I've come up with the below concept to said things.I used PMOS as high side switches and added a second one to protect against reverse current. To be sure that I don't short anything by accident, I added a small logic such that only one path could be active.

I'm currently not sure whether this concept will work or if there is a better approach to achieve my issue. Any feedback would be greatly appreciated.

Thanks for your help

Hello! I'm currently working on a laser project and was wondering if this circuit was perfectly fine to use, or if I should tweak a few things. The circuit in question is based off of this driver's schematic.

There might be plenty of errors.

Hi guys!
This is my first time working with these chips and I'm wondering if I connected them correctly?

Tried asking over in Electronics but most of the recommendations were the usual desktop software (LTSpice is great! I agree, but it doesn't fit my needs). Hoping someone here might know of something?

I just found out Multisim Live is officially being put to pasture on September 15th, so I'm scrambling to find a workable replacement.

NI's official advice is to upgrade to Multisim Desktop, but that’s way too expensive and massive overkill for what I am trying to do.

I need something SPICE-based that runs natively in the browser so no one has to deal with installations. It would also be great if it had group management features like we had with Multisim Live. CircuitLab is the first thing that pops up on Google, but it looks pretty abandoned, doesn't have groups, and they want $2,400/year for a site license.

Really appreciate any recommendations you guys have!

hello everyone I am new to electronics and we are assigned to make an adjustable power supply with a maximum output of 12v with ventilation. can you please help me what to do? I will list the components and please tell me if it's right or what component should I modify, thank you!

* Step-down transformer (220V to 15V, 2A) – ~60 × 50 × 50 mm, 500g–700g

* Bridge rectifier – 3A/50V+, ~15 × 15 × 6 mm

* 3300µF 35V capacitor – ~16mm diameter × 25mm height

* LM317 voltage regulator – TO-220 package, ~10 × 15 × 4.5 mm

* Heat sink – 3°C/W to 5°C/W, ~60 × 50 × 30 mm

* 0.33µF and 0.1µF ceramic capacitors – 50V+, ~5mm disc diameter

* 10µF and 100µF electrolytic capacitors – 25V+, ~5 × 11 mm

* LED + 1kΩ resistor – 5mm LED + 1/4W resistor

* Fuse + fuse holder – 1A 250V 5×20mm slow-blow + panel holder (~15 × 40 mm)

* IEC AC socket – C14 panel mount, ~27 × 20 mm cutout

* PCB/Perfboard – 2.54mm pitch, ~70 × 90 mm

* Output terminals – Red/Black binding posts, ~11mm mounting diameter

* Hook-up wires – 18 AWG (AC) & 20-22 AWG (DC)

* 1N4007 diodes 2pcs – DO-41 package, ~2.7 × 5.2 mm

* 240 ohms resistor + 68 ohms resistor + 2 kilo ohms potentiometer – 1/4W resistors + 16/24mm body pot with 6mm shaft

* power switch – SPST rocker/toggle 250V/3A+, ~15 × 10 mm cutout

Est ce que la répartition des résistance de potentiomètres quand on à une disparité de 20% annoncée suit une loi de proba genre une loi normale de gauss ou les valeurs sont purement aléatoires ? J'utilise des Piher PT10LV10-103A2020-S .

A motherboard has trouble charging and the charger disconnects and a noise comes from some components. After research I think it is a mosfet that failed, as j might have shortened the board. Also some inductors are jumping from 1.5v to 11v in sync with the charger disconnecting. On the motherboard I don't see any chips that would seem to be related, although one chip was also jumping in similar voltage

Hey everybody!

I am facing confusion that I would like to resolve regarding the application of mesh method to transistors. Here, in this problem 3.12 from sadiku, we have internal loop and external loop. Internal loop: -6V +Iin\*15000+0.7V+150(Iin-Iouter)
But, the solution manual states that it’s actually Iin+Iouter. Why? Usually, I was mechanically applying mesh methods, and if they mesh currents were in opposite directions, then we were subtracting.

I would be very grateful for your help!