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A passive tunable HF preselector

8 hours 4 minก่อน

Dave Richards (AA7EE) has written an article detailing his tunable passive HF preselector:

When I built the VE7BPO DC Receiver Mainframe recently, it wasn’t intended to end up as a final finished project. The intention was more to have it as part of an experimental platform. The little box that contains the DBM, diplexer, and AF amplifier that make up the mainframe will most likely stay largely the same, now that they are built and boxed up. However, the outboard functions of local oscillator and antenna filtering can swapped around and changed at will. The mainframe includes a spot for an onboard plug-in bandpass filter.

See the full post on his blog.

App note: Super Barrier Rectifier (SBR®) improves automotive supply line protection to ISO7637

จันทร์, 04/12/2021 - 00:00

App note from Diodes Incorporated on their SBR technology which can supports ISO standard supply protection. Link here (PDF)

Electrical disturbances in an automotive environment present reliability and functional risks to the various electronic systems and components that may be exposed. Many modules, for example electronic control units (ECUs), have sensitive microcontrollers at their core and must be shielded to ensure reliable operation. High-voltage transient conduction can be introduced along supply lines by many sources including: ignition systems, inductive components, unexpected conditions such as faults, and connection/disconnection of loads. Depending on the severity these can cause anything from system malfunctions to irreparable component damage.

App note: AL8860Q LED driver remote mounting and LED open/short to GND protection solution

อาทิตย์, 04/11/2021 - 20:16

App note from Diodes Incorporated on their AL8860Q LED driver with built-in faults protection. Link here (PDF)

The AL8860Q is a hysteresis mode DC-DC buck LED driver, designed for driving single or multiple series connected LEDs in automotive lamps. In some circumstances the LED string should become in fault status such as open-circuit, short-circuit, LED string anode shorted to GND, which may result in damage to the system and battery. For safety and reliability, the total solution in automotive LED lighting application must take these fault conditions in consideration.

MetaClockClock build

พฤ, 04/08/2021 - 06:59

Erich shared detailed instructions of how to build the MetaClockClock project, a set of individual analog ‘clocks’:

The ‘MetaClockClock’ project is using multiple small dual-shaft stepper motors which are usually used in instrumentation clusters. In this project multiple such motors are interconnected on a RS-485 bus and can be controlled by a master to display information or show different animation patterns.

Check out the video after the break.

Project info at mcuoneclipse.com. Files are available on GitHub.

App note: Performance comparison of 1200 V SiC MOSFET and Si IGBT Used in power integrated module for 1100 V solar boost stage

จันทร์, 04/05/2021 - 00:00

App note from ON Semiconductors comparing the performance between SiC MOSFET and Silicon IGBT in a similar and compatible power modules. Link here (PDF)

This application note compares the performance of two power integrated modules (PIMs) in the boost stage of an 1100 V solar inverter. One PIM used state−of−the−art silicon 1200 V IGBT (part number NXH100B120H3Q0) defined as PIM−IGBT and the other PIM used a new 1200 V SiC MOSFET (part number NXH40B120MNQ0) defined as PIM−SIC. These two PIMs utilized the same Q0 package technology and SiC Schottky boost diode. They are pin−to−pin compatible allowing customers to upgrade from Si IGBT to the SiC MOSFET version. Due to faster switching characteristics of the SiC device, this paper explains gate driver and PCB layout topics which must be considered when using fast switching devices like SiC MOSFETs.

App note: Characteristics and driving recommendations of ON Semiconductor Gen 1 1200 V SiC MOSFETs & modules

อาทิตย์, 04/04/2021 - 21:22

App note from ON Semiconductors on their SiC MOSFET’s key characteristics and how to drive them. Link here (PDF)

Silicon carbide (SiC) is part of the wide bandgap (WBG) family of semiconductor materials used to fabricate discrete power semiconductors. Conventional silicon (Si) MOSFETs have a bandgap energy of 1.12 eV compared to SiC MOSFETs possessing 3.26 eV.
The wider bandgap energy associated with SiC and (GaN) Gallium Nitride means that it takes approximately 3 times the energy to move electrons from their valence band to the conduction band, resulting in a material that behaves more like an insulator and less like a conductor. This allows WBG semiconductors to withstand much higher breakdown voltages, highlighted by their breakdown field robustness being 10 times that of silicon. A higher breakdown field enables a reduction in device thickness for a given voltage rating which translates to lower on−resistance and higher current capability.

App note: The thermal measurement point of LEDs

จันทร์, 03/29/2021 - 01:48

App note from OSRAM on different thermal masuring locations of LEDs. Link here (PDF)

When current passes through the junction area of a chip, light is emitted. Not only light is generated, but also a lot of heat. Good thermal management is a major factor for the stable performance of LEDs in applications. However, a high junction temperature has a negative effect on the lifetime and the reliability of LEDs.
Defining the junction temperature poses a challenge because it cannot be measured directly. However, the junction temperature can be calculated by measuring the solder point.

HP 27201A, the world’s first speech synthesizer by a major computer company

เสาร์, 03/27/2021 - 06:43

smbakeryt has written an article on reverse-engineering the protocol used by the HP 27201A:

The HP 27201A is a TMS5220 based speech synthesizer released in 1983. According to the HP museum, it’s the first synthesizer designed by a major computer computer. Yes, the TI99/4A’s speech synthesizer uses the same IC and is at least contemporary if not even predating the HP module. The module has very sparse documentation on the web, so I had to disassemble the Z8 ROM and then reverse engineer the protocol.

See the full post on Scott M. Baker’s blog.

Check out the video after the break.

Using a thermal printer mechanism

เสาร์, 03/27/2021 - 06:14

Casio CP-10 printer re-use:

I bought a CP-10 to see if I could re-use the printer mechanism instead of the receipt printers that I have bought off ebay in the past. They are relatively expensive (over £20) whereas the CP-10 can be had for half the price, if the CP-10 is listed as non-working. Unfortunately the CP-10 has a NiCd battery pack, as the printer mechanism take a fair current when running and the pack is used to supply that. This means that a lot of CP-10s have suffered battery leakage and failed. This is what had happened to my example. After a brief attempt to revive it I cut off the printer mechanism and attached a blue pill and some extra circuitry.

More details on Black Rock blog.

I2C master mode emulator

ศุกร์, 03/26/2021 - 06:59

Dilshan has published a new build:

The I2C master mode emulator allows communication with I2C devices by sending or receiving data to/from the I2C bus. To issue the I2C commands, the emulator should connect to a PC over the USB port. After initializing the emulator, the PC and directly control the I2C slave chip/module.
This emulator is based on ATmega16A MCU. The USB communication channel is develop using the V-USB firmware.

More details on Jayakody’s blog. Project files available on GitHub.

Over engineered true random value generator

พุธ, 03/24/2021 - 06:38

maker_ATOM shared detailed instructions of how to build over engineered true random value generator, project instructables here:

Random numbers are often used in daily for example in encryption, gambling, gaming and much more. These numbers are generated by computers using complex algorithm but it can be predicated if we know the seed value and the algorithm.
So this is my attempt to create over engineered and as far as possible most random number generator.

A USB microphone for online meetings

อังคาร, 03/23/2021 - 06:58

An I2S USB microphone using an INMP441 and STM32 @ Andy’s Workshop

Project files are available on Github.

Check out the video after the break.

App note: Advanced bioimaging

จันทร์, 03/22/2021 - 00:00

App note from Newport about laser microscopy. Link here

Optical microscopes have been instrumental in the study of the life sciences for centuries. Since the invention of the laser, many advanced bioimaging techniques using microscopy have been created with progress accelerating greatly in the last two decades. Limitations in optical penetration depth, due to the scattering of light, originally limited studies to thin samples and, by necessity, processes taking place outside of the organism (ex vivo). In recent years, in vivo techniques have been developed that can visualize within the living organism or cell and have led to greatly increased understanding of cell function. Any bioimaging technique requires generating a signal from each portion of the cell or organism through some method of contrast.

App note: Ophthalmic surgery

อาทิตย์, 03/21/2021 - 20:00

Great read app note from Newport about non contact treatment for eye diseases using lasers. Link here

Ophthalmology is the branch of medicine that deals with the anatomy, physiology and diseases of the eye. The laser is particularly suited to ophthalmic surgery since it can provide a non-contact method of interacting with the cornea or even the interior of the eye, including the lens and the retina. Laser photocoagulation surgery is used to treat several eye diseases and has become widely used in recent decades. Treatments for diabetic retinopathy and macular degeneration have also been accomplished with several kinds of lasers including ion lasers, dye lasers, and laser diodes. Recently, two forms of ophthalmic surgery have attracted great attention: laser-assisted in situ keratomileusis (LASIK), which is used to modify the cornea and correct vision, and cataract surgery, which can facilitate replacement of the lens when it becomes cloudy. Both procedures are accomplished with the help of ultrafast pulsed laser systems.

App note: Serial Flash Discoverable Parameter (SFDP) Introduction

จันทร์, 03/15/2021 - 00:00

App note from Macronix on how SFDP help easily use serial flash. Link here (PDF)

Serial Flash Discoverable Parameter (SFDP) standard provides a consistent method of describing the functional and feature capabilities of Serial Flash devices in a standard set of internal parameter tables. These parameter tables can be interrogated by host system software to enable adjustments needed to accommodate divergent features from multiple vendors.
SFDP provides more flexibility in vendor selection; reduces engineering resources for firmware upgrades and effectively shortens the time to bring product to the market. The value of SFDP mirrors that of Common Flash Interface (CFI) for Parallel Flash. The software engineers have been asking for a standard like this since the increased adoption of Serial Flash.

App note: Plastic package device thermal resistance

อาทิตย์, 03/14/2021 - 20:03

App note from Macronix on managing thermals of memory plastic packages devices. Link here (PDF)

Thermal system design needs to account for heat transfer at many levels: device, board, and system level. In this document we focus on device level thermal resistance, the relationship between TJ (Junction Temperature) and TC (Case Temperature), and how heat is dispersed through the air and board.

App note: Pulse capabilities for thick film power resistors

จันทร์, 03/08/2021 - 00:00

Another app note from Vishay on their thick film power resistors on pulsed application. Link here (PDF)

Vishay Sfernice offers a wide range of thick film power resistors. Our resistors are able to dissipate from 5 W up to 1100 W with a large range of ohmic values (10 mOhm up to 1 MOhm).
The pulse capability of our resistors is a key specification formany customer applications.
The energy curve in the datasheets shows the maximum energy that can be applied over a given period.
In this application note, we use the example of our LPS 800 resistor to explain a method to evaluate whether the resistor is appropriate for a given application. This method can be used for each resistor type using the corresponding pulse curve or limiting voltage from the corresponding datasheet.

App note: How to Use an SiC Diode in a PFC Circuit

อาทิตย์, 03/07/2021 - 20:10

App note from Vishay on using the SiC’s diode no switching loss on PFC circuit. Link here (PDF)

An SiC diode is the optimal choice for power factor correction (PFC) in continuous conduction mode (CCM) because its particular reverse recovery characteristics reduce switching losses to almost zero.
The selection criteria for an SiC diode are different from the selection criteria for of an Si diode in the same circuit. Usually at high frequencies in CCM, Si diodes show switching losses that are not negligible. The current capability of each diode is defined as the DC current that in a certain thermal condition brings the TJ to its limit; normally 175 °C for an SiC diode and 150 °C to 175 °C for an Si diode.
The diode’s current capability is related to the maximum power that the diode is able to manage, evaluated only with DC current. However, a PFC diode is switching, so the device should be able to manage all dissipated power, not only conduction losses.

Ultra low power LED flasher using the Padauk PFS154

อังคาร, 03/02/2021 - 06:57

Low power LED flasher on PFS154:

Flashing a LED is certainly among the first set of problems any burgeoning electronics specialist is tackling, may it be by using an ancient NE555 or, more recently, a microcontroller to control the LED. As it turns out, we can turn any trivial problem into a harder one by changing its constraints.

More details on Tim’s blog.

esp32s2Stick

อังคาร, 03/02/2021 - 06:28

Luca Dentella designed and built a USB stick powered by esp32-s2 chip, the esp32s2Stick:

esp32s2Stick is a USB device based on the esp32-s2 chip by Espressif. Thanks to the presence of an USB OTG interface, it is possible to program the chip to act as a USB peripheral (mass storage device, CDC…) and to upgrade the firmware through USB (DFU, Device Firmware Upgrade).
In addition to the basic circuit needed to run the WROVER module, esp32s2Stick offers an RGB LED and a socket for MicroSD cards.

See the full post at lucadentella.it. Project files are available on GitHub.