Table of Contents These tests are conducted on all electronic/electrical devices and equipment, to make sure they do not make devices next to them malfunction. These tests are those which are conducted to measure the power and frequency of RF emissions from devices and equipment. These emissions are categorized as those under 30MHz and over 30MHz, because of the two primary methods of EM emission from equipment, conducted and radiated. Emission Measuring Instruments Measuring Receiver Conformance tests are taken with receivers which are optimized for the purpose of taking EMC measurements. The average cost of measuring a receiver system between 10kHz to 1GHz range is between $15,000-$60,000. Spot Frequency Receiver- These are hand-held receivers that the operator uses to take readings of emissions of individual frequencies from the EUT. FFT/time Domain Receiver- Fast Fourier Transform is an algorithmic implementation of Fourier Transform that enables the measuring device to take time-domain readings and convert them into real-time frequency spectrum plots. Spectrum Analyzer- This is used to record emissions from the EUT in the full frequency spectrum, within the device’s capability. This is used to confirm the frequency range in which sport frequency reception will be required because due to their full spectrum measurement capability these devices have a small amount of error. Receiver Specifications Figure 1 The new R&S®ESR EMI test receiver uses an FFT-based time domain scan to perform stan-dard-compliant dis-turbance measure-ments up to 6000 times faster than con-ventional EMI test receivers. These are the parameters on which these devices evaluate, emission performance of the equipment under test. These parameters are defined in CISPR 16-1-1, and MIL-STD-461G, and DEFSTAN 59-411 for military tests. Transducers These devices are used to convert the emissions to be measured from the EUT into something which can be displayed onto the screen of the measuring device. These devices are able to convert the four important parameters, Radiated electric field Radiated magnetic field Conducted cable voltage, and Conducted cable current Into readings which can be displayed on the screen on the receiver. CISPR 16-1-4 is referenced while choosing transducers/antennas for EMC emission testing. LISNs and probes for cable measurements Artificial Mains Network. These devices are used to conduct voltage emissions tests on the main port. These are required to provide a defined impedance at RF across the measuring point, to test the instrument, and isolate the test circuit from unwanted interference signals on the mains supply. Artificial Hand The requirements for this are specified in CISPR 16-1-2. This accessory is used to simulate those devices which are designed for hand-held usage. This accessory is a strip of metal foil, 6cm wide and normally wrapped around that part of the EUT which will be touched by the user’s hand. Absorbing clamp and CMAD These devices are used to measure emissions above 30MHz as radiated fields. The standards used to get this apparatus is CISPR 14-1/EN 55014-1. Current Probe This is a clamp-on device that is used to measure the amount of current flowing in a cable. The standard used for this is CISPR 22/EN 55022. Near Field Probes These probes are used to detect emissions near to culprit device. These devices can be around cylindrical rod or a loop that needs to be taken near the culprit devices to take readings
Altium Circuit Studio is an entry-level but professional PCB design suite. Which offers interactive automated routing, intuitive ECAD-MCAD collaboration, integrated SPICE simulations, and unparalleled design efficiency at an affordable price point. Often compared to KiCad because of the small difference in price point. Altium CircuitStudio comes with a perpetual licence fee of $495. With its native 3D, version control and over 300,00 component library and the Altium promise. This software will definitely prove to be better than others in its class. Opening up this software showcases a deliberately minimal interface that requires lesser resources to run on your computer. This showcases the demographic this product is aimed towards. Exactly as it says on the box entry-level professionals or freelancers or undergraduate students. This is not a full-professional product which is made evident by some things like, not being able to multi-object drag and drop, remapping hotkeys (this is a very mouse-heavy program), and no.DbLib support. CircuitStudio is unable to define its place, for a perpetual license fee of $495 you get 90% of the features of Altium Designer but those last 10% are the real challenge, this means that software is limited to designing low-level PCBs, which can be good for a freelance, but the price at which you get this software may just be too high for a graduate student willing to pay $120 per year for the Altium Designer student version, but without the ability to sell your designs, which CircuitStudio offers. The best thing which circuit studio offers at this price point is the Altium component library. This software is a good investment to start your PCB design and schematic journey while getting hands-on lessons and tutorials straight from the Altium community.
Motivation is necessary to reach to our goals but discipline is needed to make them achievable. What is Bluetooth Low Energy? This series of blogs on BLE, is for anyone who is going to start with Bluetooth Low Energy. Bluetooth energy comes under the short range wireless communication protocols of IoT. So lets start by understanding what is BLE. Bluetooth is a wireless communication protocol that is started as a cable replacement technology to replace wires in devices like mouse, keyboards and etc. It operates at 2.4Ghz in unlicensed ISM frequency brand. Their are two types of Bluetooth devices: one is Bluetooth Classic(BR/EDR) and Bluetooth Low Energy. Bluetooth versions from Version 1.0 to 3.0 are referred as Bluetooth Classic and from 4.0 to latest version 5.2 are referred as Bluetooth Low Energy(BLE). Bluetooth protocol is backwards compatible. Bluetooth Classic technology is developed as a wireless standard allowing cables to be replaced connecting portable and fixed electronic devices, but it cannot achieve extreme level of battery life because of its fast hopping, connection oriented behaviours and relatively complex connection. Bluetooth Classic further has Basic Rate mode(V1), Enhanced Data Rate mode(V2) and High Speed mode(v3). In this article we will not dwell much into the Bluetooth Classic, our discussion area will be confined to Bluetooth low Energy. BLE stands for Bluetooth Low Energy, which has been created for the purpose of transmitting very small packets of data at a time, while consuming significantly less power then Bluetooth Classic. Now for working with any wireless communication protocol, their are 2 important concepts that have to be understood for it. Its Communication Protocol Architecture and Communication protocol Stack( it is the firmware implementation of the Architecture). So for proceeding with BLE, we will first understand Its architecture, about the terms like GATT,GAP, HCI and how does Bluetooth low energy works and then further will understand its stack on Nordiac devices. Click here Read more such articles:
Altium designer is a PCB schematic design and layout tool, which is used to make component libraries and custom footprints, when they are not available from the manufacturer or the suppliers website. Altium even lets the user import custom made CAD files of the component, which can later be simulated to conduct thermal, electrical and RF tests. Altium Designer even has a built in SPICE simulation tool which rivals stand alone softwares in the same class. This SPICE simulation is used to conduct stability, power dissipation, impedance matching and power transfer analysis of the circuit which will be laid out later. This lets the design team save considerable money when developmental tests cannot be performed on these circuits. Altium designer is good not only because it gives the designer tools to help his PCB design process easier but it also comes with built in solutions which include videos, documentation and webinars, which pop-up and are available on the home page when the user enters. Altium design software requires a licence to operate and can be bought for a monthly fee of 20,250 rupees or a perpetually for rupees 600,000.
What is Altium? Altium is a PCB design tool, PCB stands for Printed Circuit Boards and the designing process for a PCB include: Schematic capture, Layout, SPICE simulations, Library and footprint creation, Part tracking, sourcing and revision tracking of both the components used in the design and design itself. It is like git for PCBs and Altium provides tools and resources for all parts of the PCB design workflow.The Altium designer comes with an easy-to-use interface that has lots of features for the PCB designer, like revision control and hot-keys. Altium has 4 SoftwareAltium DesignerAltium NexusAltium Circuit StudioAltium Circuit Maker Previous Next All these software provide a robust framework for the PCB designer to acquire skills of a cross-function multidisciplinary role, because PCB design requires understanding and knowledge of electronic, electrical, and mechanical theory and implementation mechanisms like testing equipment used, designing equipment, and of course manufacturing. Altium software offers the user the ability to interact and collaborate with the mechanical, electronic, and electrical designer through various tools integrated into the software which provide a seamless and robust framework for the designer. Figure 1 Altium 3D mechanical rendering. With the increase in remote working Altium software also offer cloud storage for saving projects, rendering projects, and even saving and running SPICE simulations!
Why do we need a rectifier Circuit? Whenever DC power is needed that time, we need to convert an AC Power to DC Power and that process is known as Rectification. A simple PN junction diode acts as a rectifier. The forward biassing and reverse biassing conditions of the diode makes the rectification. Types of Rectifier circuits There are two main types of rectifier circuits, depending upon their output. They are Half-wave Rectifier Full-wave Rectifier A Half-wave rectifier circuit rectifies only positive half cycles of the input supply whereas a Full-wave rectifier circuit rectifies both positive and negative half cycles of the input supply. Half-wave Rectifier Disadvantages of a half-wave rectifier Power is delivered only during the one-half cycle of the input alternating voltage. Ripple factor is high, therefore required to give steady dc output. They only allow a half cycle through per sine wave, and the other half cycle is wasted. This leads to power loss. Full-wave rectifier FWR has two types as follows: Centre tapped full wave rectifier Bridge full-wave Rectifier 1) Centre tapped full wave rectifier Advantages of a center-tapped full-wave rectifier: The ripple factor is much less than that of a half-wave rectifier. DC load current values are twice those of a half-wave rectifier. The rectification efficiency of the full-wave rectifier is double that of a half-wave rectifier. Disadvantages of center-tapped full-wave rectifier Location of center-tapping is difficult. The dc output voltage is small. The PIV of the diodes should be high. 2) Full-wave bridge rectifier Advantages of bridge rectifier: The need for the center-tapped transformer is eliminated. It can be used in application floating output terminals; no output terminal is grounded. The transformer utilization factor, in the case of the bridge rectifier, is higher than that of a center tap rectifier. Disadvantages of Bridge Rectifiers over center tap rectifiers. It requires four diodes for operation, thus, circuit components requirements in the case of the bridge rectifier are more than that of center tap rectifiers. The voltage drop across diodes increases four times that of a center tap full-wave rectifier. Types of Components and Its Symbol used in circuit Schematic of bridge rectifier PCB Layout of bridge rectifier Track Width – 1.00 mm Bill of material During the PCB assembly process, a BOM provides information about the components under a single roof such as their quantity, reference designators, footprints, etc. Designers will save lots of time and effort during PCB design by preparing a bill of materials with all the updated parts list. Every line of the bill of materials (BOM) includes the product code, part name, part number, part revision, description, quantity, unit of measure, size, length, weight, and specifications or features of the product. Go to fabrication bar in Easyeda online tool Download BOM Gerber File Each artwork layer, copper circuitry, power, or ground must have a corresponding Gerber file to create the required pattern. The outermost layers, referenced as “top” and “bottom,” component and solder or by layer count will also have a conforming layer for solder mask and silkscreen to be applied. Summary In this second blog, we have created a schematic of bridge rectifier and pcb layout also and learnt about bill of material and Gerber file. Apart from that we have seen that type of rectifier and understood which one is suitable for industry. Reference https://www.powerelectronicsnews.com/power-supply-design-notes-rectifier-circuits/ https://www.tutorialspoint.com/electronic_circuits/electronic_circuits_full_wave_rectifier.htm https://www.allaboutcircuits.com/textbook/semiconductors/chpt-3/rectifier-circuits/
Static is a keyword in the c/cpp language. It is a storage class specifier that can be applied to any data type. A static keyword can be used with both variables and functions. The static keyword tells the compiler to make the variable or function limited to scope but allows it to persist throughout the life of a program. The static keyword limits the scope of variables or functions to the current source file only. So static keyword helps in hiding the data to one source file only. Static words help in achieving encapsulation in c language. In this blog, we are going to cover the use of static keywords with variables. Static variables are stored in BSS or data segment of the C program Memory Layout. The BSS segment contains the uninitialized data. The DATA segment keeps the initialized data. The static variable is only initialized once, if it is not initialized then it is automatically initialized to 0. void demo(int value) { static int count = 0; count = value; cout<<count; } count = value: is not initialization, it is an assignment. Static can be assigned as many times as we wish. static int count = 0: is initialization & that happens only once for static variables. We can have static global variables or static local variables. Static local variables Static variables are able to retain their value b/w function calls. Static keywords, when used with variables inside the function, are then called static local variables. Static global variables The static keywords when used with variables outside the functions, are then called static global variables. Static global variables help in achieving enumeration, that is they make the scope of the variable limited to the present file only. References: The static keyword in C (c-programming-simple-steps.com)
Here we will understand the basic terms related to microcontrollers.
Introduction to the SPI SPI stands for Serial Peripheral Interface. It is one of the most widely used interfaces between the microcontroller or other peripheral devices such as sensors, shift registers, etc. It uses a Synchronous communication protocol [It shares a clock signal for synchronizing bits between 2 devices] for the communication between a Master[ a microcontroller] and slaves[other peripheral devices]. Usually, a [Master]microcontroller sends a clock signal to the slaves to start the communication between them. SPI uses either 3 or 4 logic signals to communicate SCLK– Shared clock signal [Synchronize data transmission] MOSI– Master Out Slave In [Master sending data to the peripherals] MISO– Master In Slave Out [Master receiving data from the peripherals] CS/SS–Chip/Slave Select [Master indicates that data is being sent] How do SPI works? CS/SS – To start a new transmission the Master pulls the chip select to a low voltage level which means taking the voltage to 0. When it’s done the chip select goes back to its non-transmitting state which is a high voltage level. It is also used for selecting the slave to which master wants to communicate when we have multiple peripherals. When we have multiple slaves they are get connected by the Daisy chain. In Daisy Chain ChipSelect for all the slaves is connected together as in fig below and data propagates from one slave to the next. All the slaves receive the clock signal at the same time. Master sends the data to the first slave and so on. When the data is transferring from one slave to the next, The number of clock cycles required to transmit data is proportional to the slave position. Ex: Assuming we have 2 slaves and we need to transfer the data to the second slave. We have an 8-bit system then we need to send 16 clock pulses[8clockpulses at once as we are taking an 8-bit system] to get to the second slave. But Daisy Chain is not supported by all devices. Reading Data Sheet is recommended for that. SCLK – In SPI the clock signal is generated by the Master. The Master configures the clock, using a frequency supported by the slave device, and sends the clock signal to synchronize the data. Clock Polarity and Clock Phase are the main parameters to define a clock signal which is described later. MOSI/MISO – As SPI is full-duplex, the Master can transmit and receive the data bit by bit at the same time. Master sends the data in series usually MSB goes the first and in MISO, the slave sends the LSB first to the master. Modes of transmission CPOL[clock polarity]- It is used to determine the idle state of the clock. CPHA[clock phase]- Clock Phase determines at which edge data read/write occurs which is described in modes of transmission. If CPOL = 0 , data read/right occurs at falling edge then CPHA=0 If CPOL = 0 , data read/right occurs at rising edge then CPHA=1 If CPOL = 1 , data read/right occurs at rising edge then CPHA=0 If CPOL = 1 , data read/right occurs at falling edge then CPHA=1There are 4 modes of transmission in SPI: Data Transmission Steps The Master selects the chip select line associated with the slave. The Serial Clock line is then enabled. Master starts sending one bit of data on the MOSI line with each clock pulse. Slave reads the MSB first and stores it into memory. MISO line sends the data to the Master. Master reads the LSB first and stores it into the memory. Applications of SPI Memory: SD Card, MMC, EEPROM, Flash. Sensors: Temperature and Pressure. Control Devices: ADC, DAC, digital POTS, and Audio Codec. Others: Camera Lens Mount, touchscreen, LCD, RTC, video game controller, etc