Basic Electronics category

PNP Transistor – How Does It Work?

The PNP transistor is a mystery to many. But it doesn’t have to be. If you want to design circuits with transistors, it’s really worth knowing about this type of transistor. by Oyvind @ build-electronic-circuits.com

PNP Transistor – How Does It Work? – [Link]

Sensing current on the high side

Michael Dunn @ edn.com writes:

At their heart, the majority of DC current sense circuits start with a resistance in a supply line (though magnetic field sensing is a good alternative, especially in higher-current scenarios). One simply measures the voltage drop across the resistor and scales it as desired to read current (E = I × R (if I didn’t include this, someone would complain)). If the sense resistor is in the ground leg, then the solution is a simple op-amp circuit. Everything stays referenced to ground, and you only have to be careful about small voltage drops in the ground layout.

Sensing current on the high side – [Link]

easyeda online circuit simulator

Top Ten Online Circuit Simulators

Online circuit simulators are getting more popular day by day. Electronics hobbyists, as well as professionals, use circuit simulators often to design and check circuit diagrams. The best thing about online simulator is, you don’t have to install anything at all on your PC or laptop. All you need is a browser and a stable internet connection. Work from anywhere just by opening the online circuit simulator website and signing in to your account. Cool, huh?

Now the question is, which simulator should one use? Which one is the best simulator? Well, in one sentence, “there is NO best simulator“. It depends on your requirement and level of expertise. If you are just a beginner, then you need a basic and less complex simulator. But if you’re professional and very expert in this field, obviously you’ll need a complicated, multipurpose simulator.

Here I’ve listed top ten online simulators based on their popularity, functionality, pricing, and availability of library parts.

1. EasyEDA

easyeda online circuit simulator
EasyEDA online circuit simulator

EasyEDA is a free, zero-install, web and cloud-based EDA tool suite which integrates powerful schematic capture, mixed-mode circuit simulator and PCB layout in a cross-platform browser environment, for electronic engineers, educators, students, and hobbyists.

As EasyEDA is completely free, super easy to use, and feature-rich, it holds the first place.

 

Pros: 

  •  Huge and ever growing community
  • Parts library is quite massive
  • Very powerful simulator
  • High-quality PCB designing is possible
  • Designing circuit/PCB is free from any kind of hassle. Beginners can easily get started to EayEDA
  • EasyEDA is completely FREE

Cons:

  • Getting the simulation done is kinda difficult. You need to follow the guide.

2. circuits.io (Autodesk Circuits)

(circuits.io) Autodesk circuits online simulator
(circuits.io) Autodesk circuits online simulator

Autodesk Circuits empowers you to bring your electronics project ideas to life with free, easy to use online tools.

A circuit/PCB designing tool and simulator developed by AutoDesk, empowering you to design the circuit, see it on the breadboard , use the famous platform Arduino, simulate the circuit and eventually create the PCB. You can program the Arduino directly from this software simulation.

Pros:

  • The output design is easier to interpret and will be a handy reference while making a real life connection
  • It can simulate Arduino
  • The library has plenty of parts

Cons:

  • Designing circuit is bit tougher than other simulators
  • Can’t draw a circuit quickly

3. PartSim

PartSim online Circuit Simulator
PartSim online Circuit Simulator

PartSim is a free and easy to use circuit simulator that runs in your web browser. PartSim includes a full SPICE simulation engine, web-based schematic capture tool, and a graphical waveform viewer.

Pros:

  • This platform is pretty neat and easy to use
  • Large number of parts from vendors makes this a good choice for practical purpose
  • PartSim is entirely free to use

Cons:

  • Not so powerful simulator but ok for beginners
  • It has a lot of op-amps in library but other ICs lack

4. EveryCircuit

EveryCircuit Online Circuit Simulator
EveryCircuit Online Circuit Simulator

EveryCircuit is an online circuit simulator with a well-designed graphics. It’s really easy to use and has a great system of electronic design. It allows you to embed simulation into your web page.

Pros:

  • EveryCircuit is also available mobile platforms (Android and iOS)
  • Impressive animated representation of various dynamic parameters
  • It offers plenty of example and pre-designed circuits. Good for beginners

Cons:

  • This platform is not a free one
  • It lacks many useful ICs

5. Circuit Sims (Falstad Circuit)

Falstad Circuit Online circuit simulator
Falstad Circuit Online circuit simulator

Extremely simple web platform that runs on any browser. The platform perfectly suits beginners who want to understand the functionality of simple circuits and electronics.

Pros:

  • The simplest one. Beginners won’t have to struggle with it
  • Completely free and no account is required
  • This is an Open-Source platform

Cons:

  • The library parts are very limited
  • GUI is not attractive

6. DC/AC Virtual Lab

DC/AC Virtual Lab online circuit simulator
DC/AC Virtual Lab online circuit simulator

DC/AC Virtual Lab is an online simulator who is capable of building DC/AC circuits, you can build circuits with batteries, resistors, wires and other components.

DC/AC Virtual Lab has a pretty attractive graphics and components are real looking, but it is not in top fives because of limitation in parts library, incapability of drawing circuits and some other reasons.

Pros:

  • Simple UI, good for students and instructors
  • Parts look like real one, not just symbols

Cons:

  • DC/AC Virtual Lab is NOT completely free
  • Parts library is very much limited
  • Simulation is not that powerful

7. DoCircuits

DoCircuits online circuit simulator
DoCircuits online circuit simulator

DoCrcuits is easy to use but not much efficient. You can design both analog and digital circuits. But you have to log in to get the simulation done.

Pros:

  • Interactive design, though a bit sluggish
  • Components are real looking
  • Many readymade circuits are there

Cons:

  • You can’t use both analog and digital components on the same circuit
  • Simulation is pretty much limited
  • DoCircuits is NOT free

8. CircuitsCloud

CircuitsCloud online circuit simulator
CircuitsCloud online circuit simulator

CircuitsCloud is a free and easy-to-use simulator. It works good for both analog and digital. Beginners can easily use it but have to create an account first.

Pros:

  • CircuitsCloud is a free platform
  • Making circuit is easy here

Cons:

  • Simulation is not good. Doesn’t animate direction of current
  • Library doesn’t contain enough digital IC and MCUs

9. CIRCUIT LAB

CircuitLab online circuit simulator
CircuitLab online circuit simulator

Circuit Lab is a feature-rich online circuit simulator, but it’s not free. It’s designed with easy to use editor and accurate analog/digital circuit simulator.

Pros:

  • This platform is well-built with fairly extensive library that is suitable for both beginners and experimenters
  • Simulated graphs and output results can be exported as CSV file for further analysis
  • Designing circuits is easy and pre-designed circuits are available

Cons:

  • This is not a free platform but you can use the demo for free
  • The simulation could have been better with interactive simulations apart from the graphical representation
  • More digital ICs should be added in library

10. TinaCloud

Tina Cloud online circuit simulator
Tina Cloud online circuit simulator

TINA Design Suite is a powerful yet affordable circuit simulator and PCB design software package for analyzing, designing, and real time testing of analog, digital, HDL, MCU, and mixed electronic circuits.

TINA is a very sophisticated circuit simulator and a good choice for experienced persons. It’s not very easy for beginners and takes a while to get started. TINA is not free. But if you consider the performance, the price is negligible.

Pros:

  • This simulation program has sophisticated capabilities
  • Simulations are performed on company’s server, hence it provides an excellent accuracy and speed
  • Various types of circuits can be simulated

Cons:

  • This platform is NOT for beginners
  • Even if you are experienced one, initially you may face some difficulties
  • Tina Cloud is NOT a free simulator
Others:

So, now you have a list of “Top Ten Online Circuit Simulators”, but this isn’t a final one. There are other online simulators which you may find as good for you. simulator.io, Gecko-SIMULATIONS etc. are some of them. I recommend you to try all of them before choosing one as perfect.

If you have any other online simulator in your knowledge to share with us, please do. Any suggestion is highly appreciated.

LC-04 4 Channel Logic Converter 3.3V – 5.0V

If you have ever tried to connect a 3.3V device to a 5V system, you know what a challenge it can be. The LC-04 bi-directional logic level converter is a small device that safely steps down 5V signal to 3.3V and steps up 3.3V to 5V at the same time. In this instructable, mybotic explained the procedure to use the LC-04 bi-directional logic converter.

Description:

The LC-04 module offers bi-directional shifting of logic level for up to four channels. The logic level HIGH (logic 1) on each side of the board is achieved by 10K Ω pull-up resistors connected to the respective power supply. This provides a quick enough rise time of logic level to convert high frequency (400KHz I²C, SPI, UART etc.) signals without delay.

This module has the following features:

  • Dual-supply bus translation :
    • Lower-voltage (LV) supply can be 1.5 V to 7 V
    • Higher-voltage (HV) supply can be LV to 18 V
  • Four bi-directional channels
  • Small size: 0.4″ × 0.5″ × 0.08″ (13 mm × 10 mm × 2 mm)
  • Breadboard-compatible pin spacing

    The bi-directional level-shifting circuit
    The bi-directional level shifting circuit

The Pinout:

The LC-04 logic level converter has two types of pins:

  1. Voltage input pins :
    • 2 pins (GND and LV) on Low Voltage  side
    • 2 pins (GND and HV) on High Voltage  side
  2. Data channels :
    • 4 pins (LV1, LV2, LV3, and LV4) on Low Voltage  side
    • 4 pins (HV1, HV2, HV3, and HV4) on High Voltage  side

Pin HV and LV set HIGH (logic 1) logic level on High voltage side and Low voltage side respectively, with respect to the GND.

Data channel pins shift logic levels from one voltage reference to another. A low voltage signal sent into LV1, for example, will be shifted up to the higher voltage and sent out through HV1. Similarly, a high voltage signal sent into HV1 will be shifted down to the lower voltage and sent out through LV1.

LC-04 Bi-directional logic level converter pinout
LC-04 Bi-directional logic level converter pinout

Parts List:

  1.  LC-04 4 Channel Logic Level Converter
  2. Arduino Uno Board and USB Cable
  3. Breadboard
  4. Crocodile Clip (optional)
  5. Multimeter

The Wiring:

The wiring is pretty simple. You may even omit the breadboard by making end-to-end connections. Two types of connections are required:

  1. Pin connection to shift down (5V to 3.3V)
  2. Pin connection to shift up (3.3V to 5V)
Pin Connection to Shift Down:
  1. LV to 3.3V
  2. LV’s GND to multimeter’s black probe
  3. LV3 to multimeter’s red probe
  4. HV to 5V
  5. GND to UNO’s GND
  6. HV3 to Digital Pin 4
Logic level shift down using LC-04 logic level converter
Logic level shifting down using LC-04 logic level converter
Pin Connection to Shift Up:
  1. LV to 3.3V
  2. LV’s GND to UNO’s GND
  3. LV3 to Digital Pin 4
  4. HV to 5V
  5. GND to multimeter’s black probe
  6. HV3 to multimeter’s red probe
Logic level shifting up using LC-04 logic level converter
Logic level shifting up using LC-04 logic level converter

Load switch with self-resetting circuit breaker

di5467f1

has designed a simple load switch using two transistors and some resistors.

The simple current-limiting load switch shown in Figure 1 will be familiar to most readers. In this circuit, a high level signal applied to the input switches on MOSFET Q2, which energizes the load. The load current is limited by negative feedback applied via Q1.

Load switch with self-resetting circuit breaker – [Link]

How to Choose a Connector

connectors

Sanket Gupta @ octopart.com discuss on how to choose a connector. He writes:

Continuing our series about choosing parts, inspired by the latest version of the Common Parts Library, let’s take a close look at how to find and select connectors. In this blog, we will explain all the different types of connectors, their merits and demerits, and their popular applications. We will also recommend some commonly used connectors with high supply chain availability to help you find the right connector.

How to Choose a Connector – [Link]

Thermal design: Get the heat out of the electronics

hausermann_hsmtec_pcb
Häusermann has a propriety process that makes PCBs that can conduct a great amount of heat or current.

@ edn.com discuss about thermal design in electronics and how to design your board to dissipate it effectively.

If you have high-powered LEDS, or a power supply, or are trying to control larger motors, you have to get a lot of heat out of your circuit boards. The classic way to dissipate heat is to bolt your power transistor to an aluminum heat sink. That is a slow, messy, and expensive proposition, especially if you need thermal grease between the transistor and heat sink.

[..]

It’s always a good idea to make thermal management inherent in your PCB design. Experience has shown you can get about 2W of heat out of a 3×5” copper area on a conventional FR4 PCB.

Thermal design: Get the heat out of the electronics – [Link]

Measuring the speed of light with electronics

The speed of light in vacuum is a well-known universal constant and is considered to be the nature’s ultimate speed limit. No matter, energy, and information can travel faster than this speed. The speed of light has always been a topic of great interest and significance throughout history. In the course of measuring the speed of light, scientists have explored numerous ingenious approaches from analyzing the motion of heavenly bodies to artificial quantitative measurements in the laboratory. Michael Gallant describes a very simple approach of measuring this physical constant using an infrared LED, a photodiode circuit, and an oscilloscope. The premise of this method is to allow an infrared beam to travel different distances and then compute the time delay (Δt) between them using the oscilloscope. By measuring the difference in the distances (Δd), the speed of light can be calculated as the ratio of Δd and Δt.

IR Light source
IR Light source

The following diagram describes the setup he used. A Vishay 870 nm IR LED (TSFF5210) generates an IR pulse beam that splits into two beams (L1a and L0) through a beamsplitter (BS). L0 is directly focused onto the photodiode (Pd) using a lens. The L1a beam gets reflected off a mirror, travels along the path L1b, and then focused using a different lens onto the same photodiode. You can see the net path difference between the two beams before they hit the photodiode is (L1a+L1b – L0). If the original IR pulse is kept adequately short, the two optical pulses detected by the photodiode will not overlap in time. An oscilloscope of sufficient bandwidth can therefore reveal the time difference between the two pulses. The photodetector used in this setup was Vishay BPV10 high speed Si pin type with a bandwidth of 200 MHz. The photodiode signal is amplified using an AD8001 Opamp based preamplifier circuit with a gain of 35 (31 dB) and BW of 50 MHz.

Experimental setup for measuring the speed of light
Experimental setup for measuring the speed of light

Michael measured the path difference of the two beams to be 1851 cm and the difference in the time of flight to be 62 nanoseconds from the oscilloscope. This results in the measured speed of light to be 298548387 m/s, which is remarkably accurate for such a simple setup.

Time difference between the arrival of the two pulses can be seen on the oscilloscope
Time difference between the arrival of the two pulses can be seen on the oscilloscope

Find more about this project.

Basic Electronics – How to use a 555 Timer

Do you want to know how to use a 555 timer? Laura brings you more Back to School tips and tricks on using this integrated circuit.

Basic Electronics – How to use a 555 Timer – [Link]

How Boost Converters (DC-DC Step-Up) Works

A look into how boost converters work in a very visual format. Try this circuit: http://goo.gl/nkHq9H

How Boost Converters (DC-DC Step-Up) Works – [Link]