Questions tagged [schematics]

The diagram that shows how the parts are hooked up logically. If your question is about a specific schematic software package, use that tag instead.

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44 views

How to know if my custom made arduino schematic is working? [on hold]

I made my own Arduino schematic based on Arduino Due's schematic and added an MPU6050 to the board. --Also I'm not certain that every component I'm using is necessary to my board (fig1), do you have ...
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136 views

Please check my board design before I waste money

TL;DR: Please make sure my schematic and board design won't blow up on me. GitHub Repo if you're feeling extra thorough. Project overview I am trying to create an Arduino based Bluetooth RGB led ...
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2answers
426 views

What is the meaning of “do not populate test points” in a board schematic

I was finding test points in a schematic of an Analog Devices Evaluation board. In one of the schematic pages, there is a clause mentioned "do not populate test points". Does anyone knows what it ...
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48 views

What are the additional transistors used for in this hex inverter?

I'm learning about electronics and was studying the SN7404 hex inverter schematic when I saw this: I naively expected just a single transistor (the one in the bottom right) and the input at the base ...
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1answer
37 views

Baxandall tone circuit passes signal through but does not alter its tone

I added an Baxandall active tone circuit to an existing overdrive circuit and I'm having an issue. The signal passes through the circuit/opamp and out to my volume control but the bass and treble ...
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31 views

Pin confirmation on pic for sd card connector?

I've had a first version of a connection to a sd card connector (DM3CS-SF) for my PIC32MX470F512L that did the following connections: After trying to run an harmony example, using this config, the sd ...
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1answer
76 views

What could be the reason these wires need to be connected outside of the sensor?

Below diagram shows the inner system of a wind-meter and four output wires to power it and collect the 4-20mA output signal as current or voltage by using a resistor. I verified with a voltmeter's ...
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1answer
70 views

Problem with boost converter

I am currently trying to use the LMR61428 boost converter IC with the configuration in the attached schematic and having an heating problem with the inductor. The inductor gets very hot very fast even ...
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1answer
84 views

What is this dumbbell looking symbol on this schematic? (looks like jumper pad, but with a short)

Regarding to SJ1 and SJ2 in this schematic: On the board it looks like two ordinary copper pads but with a thin connection between them. Is it meant to be a way to open the circuit by scraping off ...
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2answers
83 views

I need some help understanding the schematics of DIY HS102 oscilloscope

I was looking on the schematics for the DIY HS102 oscilloscope by Martin Loren (http://hscope.martinloren.com/HS102-oscilloscope.html) But I'm a bit confused about the role of the ASM1117 (LDO ...
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37 views

Guitar to iPhone JFET pre-amp circuit issue

I am following this tutorial to build a simple JFET pre-amp to connect a guitar to an iphone. This is the schematic: I have soldered the components as per the schematic directly onto the 1/4" mono ...
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29 views

24-60V Precharge schematic critique

I'm looking to design a soft-start precharge circuit for starting up circuits with substantial input capacitance (~1.5J @ 24V). The main requirements are: 24-60V compatible Constant current pre-...
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45 views

How does this circuit work (digital logic circuit?)

I don't really understand how this circuit works. For example, suppose that Reset (Num 7) is 0, Thresh (Num 8) is 1, and Trig (Num 9) is 1. After Y1 we get "1", after Y2 "1" too. And logic "1" ...
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1answer
65 views

How to drive a speaker with amplifier using 3.5 mm jack [closed]

I have two bare loudspeakers salvaged from old speakers and I would like to control them from computer using 3.5 mm jack. The speakers had a control board, but that is broken. I would like to ...
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32 views

ESP32 with LNA and PA

I would like to add a low noise amplifier and a power amplifier to the ESP32. As you may know there is only one RF output on the chip. I was thinking of adding an RF switch, and switching between ...
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28 views

Using ESP32 and external WatchDog STWD100NYWY3F

I want to use ESP32 with the STWD100NYWY3F external watchdog timer. Below is my connection diagram. On WDI with 33 pin, periodic pulses are sent to the watchdog timer. If the timer is not reset, then ...
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1answer
31 views

AC Mosfet linear control

So I'm developing a circuit to control charge, discharge and balance LiPo batteries. Supply voltage will be ranging from 7V to 25V, but not larger than max. Voltage of charged battery. (If I connect 2 ...
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2answers
87 views

What is the use of these resistors in the schematic?

I am trying to build a line-following robot with the schematics I found below. I understood that the comparator is used as the logic for the robot and there is no need for a feedback loop for the ...
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1answer
38 views

Transmitter / Amplifier matching

I am trying to add an amplifier to a transceiver to increase the range but I am not sure how to add the reference schematics together (eg what components to remove, combine, etc). The top schematic ...
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1answer
47 views

Enterprise model blinkers - two fast flashes and pause for 3s and repeat LED circuit (with 555 and/or 556 and/or 4017) [closed]

I'm building a Revell Enterprise Into Darkness model with LEDs and I need help with circuit that makes two fast flashes, pauses for 3 seconds, then repeats. as seen in the movie. I have searched and ...
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3answers
878 views

What is a Power on Reset IC?

I'm making a prototype based on the W7500P reference design, the latest version (updated 6 months ago) specifies the need for a Power over Reset IC. I do not understand the point of this component ...
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1answer
88 views

Is this an appropriate smps design? [closed]

I am an engineering fresh graduate with an interest in PCB design. I have been learning KiCAD which is really fun and I enjoy it alot. A friend came to me with the reference circuit attached here and ...
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1answer
54 views

Checking my mpu6050 schematic

I am fairly new to pcb design and I just created a mpu6050 chip that will work with an Arduino microprocessor. I want to make sure the hookup is all correct before I start work on the other parts, as ...
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1answer
79 views

Faster refactoring in Altium Designer 19: Quickly converting a circuit fragment to a new sub-sheet

In the process of refactoring a large schematic sheet into smaller, more manageable, hierarchical sheets in AD19 I have the following process: Create a new schematic sheet for the sub-circuit and ...
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138 views

Could i get some circuit design feedback?

I have a computer science background and this is the first circuit I've ever designed. It is a lot of fun designing these circuits, but it also always feels like I'm missing a lot of "obvious" common ...
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1answer
34 views

Notation for switches in ladder notation

I was reading https://www.allaboutcircuits.com/textbook/digital/chpt-10/monostable-multivibrators/, and at the bottom of the page it has I read their page on switch notation, but it did not say what ...
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2answers
113 views

ESP32 powered by supercapacitors

It's been ages since I had to design something electrical so please don't laugh if this is stupid idea but I would like to power ESP32 with super capacitors, just for 30 sec or so so it can finish the ...
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2answers
1k views

Learning how to read schematics, questions about fractional voltage in schematic

In a schematic I've been reviewing I see in only one spot that there is a 1/2v going somewhere? What does that mean? simulate this circuit – Schematic created using CircuitLab
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2answers
121 views

Butt splice electrical symbol

I'm making a detailed electrical diagram which needs to include splices. From researching on Google I couldn't find the conventional symbol for a butt splice, or even a splice, in an electrical ...
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0answers
26 views

CircuitStudio: How to connect zero-indexed buses to a repeat schematic sheet?

The general gist of what I'm trying to do (in CircuitStudio), is the following: In a hierarchical block "input", I generate four signals that are to be fed to an array of sensors, one signal per ...
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1answer
61 views

Question about Roland 606 schematic

Hello this is my first post. I have a question regarding the circuit diagram of the Roland 606. I'm currently redrawing the hihat circuit with noise unit. The symbol behind R6, and elsewhere in the ...
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68 views

Help identify RJ11 pins on a relay board - No152133

I'm tinkering with my garage door motor (Marantec Comfort 220) which have a RJ11 6-pin connector (X10) for an accessory relay board. The board consists of three (3) relays driven via the RJ11 ...
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2answers
159 views

What is the correct schematic symbol to use for virtual ground?

I'm following the design of a circuit requiring a power supply to provide something the author calls virtual ground, \$V_{gnd}\$. The circuit look like this: However, I'm using KiCad for the design ...
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1answer
110 views

Will this capacitive discharge welder design work?

I'm an electronics newbie trying to learn about the subject through tinkering, and my current project is a capacitive discharge welder for welding on battery terminals. I thought I'd better have ...
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3answers
97 views

eagle schematic check [closed]

I will do basic IOT project with esp-wroom-32. but I am machanical student. I need to help please check my design. my component: - esp-wroom-32 - button - pad-resistor - locig level converter - ...
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51 views

How does recuperation works in BLDC?

Using BLDC wheels is common on electric transport. A wheel is a multiphase motor, where each phase(coil) is separated from power source(battery) with some kind of transistor, driven by PWM-like signal....
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1answer
92 views

Why is this power supply split?

I am looking at a schematic for the Pixhawk 2 board. It has a complex power distribution system (see photo below) Much of the complexity exists for one of two reasons redundancy shutting off ...
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1answer
64 views

Connecting an IC to LEDs - would I use a transistor?

I have this breadboard circuit, which is basically a 65C02 CPU that has 16 Address pins. I want to wire these up to LEDs. Below, I've connected them directly, which is likely all kinds of bad (Too ...
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1answer
85 views

How to drive 2/3 color LED's and circuit schematic

I need to use 2 or 3 color LED for my circuit.(preferably 3 color one). I am going to use PIC18F26K83 to control the LED. However, I am confused how am I going to make it change colour. I think I ...
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1answer
31 views

eeschema: prevent Value, Reference from moving relative to symbol library?

When I create a symbol in the symbol editor and then drop it into a schematic, many of the fields (Value, custom fields) are automatically moved outside the bounding box of graphical objects. In the ...
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1answer
30 views

How to properly use a shut pin in audio connector to prevent floating pins when disconnected

I'd like to use this RCA jack in a project that detects roughly the volume level on an RCA audio source. The circuit filters out the DC line voltage, amplifies it with a PNP transistor and then shifts ...
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1answer
165 views

Understanding 5V to 1.8V UART level-shifting circuit

Hopefully it's OK to ask very basic electronics questions here. I had a TTL 5V UART cable, however the board I had only accepts 1.8V max. So I found some online schematics that uses resistors and a ...
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1answer
60 views

What is this contact on a jack socket schematic?

I'm looking for a 4-poles (TRRS) 3.5mm jack socket with integrated switch, and stumbled upon this connector schematic: (this is an extract from the CLIFF FC68129 datasheet) I understand that pins 1, ...
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1answer
57 views

How to diagram power-side and ground-side switches?

I'm an early-stage self-teaching hobbyist. Just as a practice exercise I'm diagramming simple circuits (without looking at the instructions) of DIY kits that I've bought on banggood.com (awesome ...
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1answer
40 views

LCSC parts for Coil & Capacitor

Greeting, I'm using This Schematic as a reference to create a customized BLE PCB board. I need some help to identify the below parts (with LCSC part No. if possible) as this is my first time to see ...
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2answers
738 views

Schematic conventions for different supply rails

I have two ICs in my circuit. They have different supply voltages, 3.3 and 2.7 volts. The voltages are subject to change as we refine the design. I'm trying to come up with labels for these rails. One ...
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1answer
66 views

PSpice AC Circuit Simulation Showing 0 V for Output Voltage?

I am trying to run a simple Op Amp simulation. My lab gives zero instruction on PSpice, tossed us a brief manual on DC PSpice circuits (even though the class is AC), and said go forth. The circuit I ...
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1answer
302 views

Help understanding 1986 schematic for Rohde & Schwarz cryptographic key generator

From https://www.cryptomuseum.com/crypto/rs/pu104/index.htm :- PU-104 was a key generator for perforated paper tape, made around 1986 by Rohde & Schwarz (R&S) in München (Munich, Germany). ...
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45 views

Designing a prototype pcb in Eagle with other parts imported?

I am protyping a project with several boards like microcontroller, charger, booster etc. for my bachelor's degree in electrical engineering. Now I want to switch from my prototype board and etch my ...
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2answers
64 views

Replacing elements in a tube amplifier

I assembled a tube amplifier.According to the specified scheme (Old Russian radio "Record 66"). 1.What is the function of capacitors C9 and C8 ? 2.What will change the capacity of these parts? Will ...