One example for all – we compared super bright red LED Kingbright SR-J4 with a standard type of the same producer.
Comparison of features is usually the most exact method how to compare two similar components. But what´s the result in praxis? At such a parameter like luminous intensity, we´re probably the most interested in a subjective perception – how it shines in a real design. That´s why we decided to bring you a direct comparison. On the left side, there´s always a high efficient LED from the SR-J4 series, namely L7104SRC-J4 and a standard quality LED from the L-934SRC-C series is on the right side (it´s worth to mention that even this type has a higher than standard luminous flux). LEDs were connected in series, so they were driven by the same current. We used two common values – 1 mA and 10 mA.
And a conclusion? Both types have their advantages – the standard type mainly in the price. In respect to a very affordable price of a more efficient type, it´s more advisable to use this new type SR-J4 as well as other similar, for example series ZGK, SRY and other. In result, an efficient type will always bring a lower power consumption, longer battery life, trouble-free connection to logic circuits etc.
We got light on luminance of universal LEDs - [Link]
This tutorial presents the basics of the varactor diode, or varicap diode, and describes how it functions as a voltage controlled capacitor. A test fixture is shown and used to measure the capacitance vs. reverse voltage. Finally, a voltage-controlled oscillator circuit is built and measured, showing how the voltage on the varactor diode is used to tune the frequency of the VCO.
Basics of Varactor Diodes | Voltage Controlled Oscillator VCO Example - [Link]
anool @ wyolum.com builds a pulse lamp controller for the parking light of his KTM bike. He writes:
My brother is a Mechanical Engineer who loves his KTM Duke 200 bike. He asked me to build this circuit : http://sunbizhosting.co.uk/~spiral/blog/?p=227 for a ‘heartbeat’ lamp controller for the parking light. A Neutral Detect (ND) signal controls the lamp pulsing. When ND is HIGH, the Lamp is fully lit. When ND goes LOW, the lamp starts pulsing.
I’m not familiar with PIC microcontrollers, and didn’t want to dabble in “C” code. I’d be comfortable with an Arduino, but even the smallest ATMega seemed too big (and overkill) for this simple requirement. How about an ATTiny ? A bit of Googling, and I found this excellent resource for running the Arduino environment on the ATTiny : http://hlt.media.mit.edu/?p=1695
p.u.l.s.e. – fader control for Motorcycle parking Lamp - [Link]
Jan Rychter @ jan.rychter.com designed his own Nixie power supply that except the high voltage has two voltage outputs to power the logic circuitry, he writes:
This project is a HVPSU (High-Voltage Power Supply) that generates up to 220V from a 12V input. In addition to that, it also provides 2*Vout (so, up to 440V, for dekatrons), and two outputs for powering digital logic: 5V and 3.3V. The primary HV boost circuit reaches 88% efficiency when going from 12V to 185V at 55mA, with a 3% output ripple.
I designed it because I couldn’t find anything that would make sense for my Nixie projects. There are plenty of tiny power supply modules available on eBay, but most of them end up being impractical: no 3.3V (for my microcontroller) and 5V (for my 74141 nixie drivers), no mounting holes, no >400V output for powering dekatrons. Some supplies make a token gesture towards practicality by sticking a 7805 on the same board, but you quickly find out that the current draw of 6×74141 is enough to require a large heat sink on a 12V-powered 7805 (one 74141 consumes 12.5mA!). This means that instead of a single-board power supply you end up routing your input power all over the place, implementing your power supply in several places.
High Voltage Power Supply for Nixie Tube Projects - [Link]
Alan Parekh @ hackedgadgets.com bought a photo-switch on ebay and takes a look inside. He writes:
I spotted this photoswitch on eBay and had to take a look at the guts (search photoswitch if the link doesn’t work since eBay links go stale after a short time). I now see that the same unit is sold in multiple variations which are 24V and 220V. Not sure I would feel safe with 220 on this thing though. I am curious if the 10 ohm resistor is the only difference between the versions. If someone has one of the other versions leave a comment to let us know what the difference is. These are selling for $3.39 which included free shipping from China to Canada! Hard to believe how tilted the scales are here, I wouldn’t be able to ship this within my city for $3.39. The unit is powered from 12 volts AC or DC, it also switches the same power to the third output wire when activated. The circuit is using a 555 for operation. When the photocell goes from light to complete darkness the relay activates in 3 or 4 seconds. You can view full resolution images here.
eBay Photoswitch Teardown - [Link]
Raj @ embedded-lab.com writes:
This instructable describes in detail the setting up a full-featured weather station that records air temperature, relative humidity, and ground surface temperature right below the weather station. The project uses Phidgets SBC3 computer board, which is powered by an 18-watt solar power along with a battery backup.
PhidgetSBC3 based solar-powered weather station - [Link]
The eye-strain implications alone are staggering.
To promote the upcoming Exceptional Hardware Software Meeting (EHSM) in Hamburg, Germany, a team of DIY artists and scientists has etched the world’s smallest comic strip on a single human hair.
Titled “Juana Knits The Planet,” the strip was created by German artist Claudia Puhlfurst, then carved into the hair using a process called focused ion beam (FIB) etching. “A very sharp and high-speed jet of matter is produced and directed towards the hair to etch it — similar to a fine laser beam,” according to the project’s YouTube page.
Each of the strip’s 12 frames measures in at around 25 micrometers. A micrometer, or micron, is one millionth of a meter. A typical human hair is anywhere from 20 to 200 microns in width.
The second annual EHSM event bills itself as a meeting of international makers, hackers, scientists and engineers aiming to deliver on the “third industrial revolution.” The rest of the conference looks pretty trippy, too.
Among the presentations: electron beam welding, quantum cryptography and the interesting things that happen when molten glass, heated to 1,260 degrees Celcius, hits water. I’ve always been curious about that.
World’s Smallest Comic Strip Etched Onto Human Hair - [Link]
Alan Parekh of Hacked Gadgets writes:
Thanks to Circuit Specialists for sending in this 3 chanel power supply. The Hantek PPS 2320A sure packs in a ton of features for the price. The video below goes through the unboxing of the power supply and a quick run through its features. Overall it functions quite well, there are a few questions that need some clarification. I will have a look through the manual and reach out to the guys over at Circuit Specialists if I can’t find the answers.
Hantek PPS 2320A review - [Link]
By Tahar Allag, Wenjia Liu:
Cell phones are a good example of how functionality and performance have both increased significantly in portable devices over the last few decades. They have become more complex and can do many basic tasks as well as any computer. The extra functionality that has transitioned the smartphone from a phone-call-only device to a multipurpose portable device, which makes it more power hungry than ever before.
The internal battery pack is the main source of storing and delivering power to portable-device circuitry. Batterycharger ICs are responsible for charging the battery pack safely and efficiently. They must also control the power delivery to the system to maintain normal operation while plugged in to wall power. The battery pack is required to store a large amount of energy and be charged in a short amount of time without sacrificing weight and volume. The increased charge and discharge currents, as well as the smaller physical size, make the packs vulnerable to physical and thermal stresses. Therefore, battery chargers are no longer required to perform just as a simple standalone charger
AppNote: Battery charging considerations for high-power portabledevices - [Link]
Designers of rechargeable battery-powered equipment want a charger that minimizes charge time with maximum charge current by maximizing the power taken from the supply without collapsing the supply. Resistances between the supply and the battery present a challenge. This article explains how to design the charging circuit to achieve the maximum power from the adapter despite the undesired resistances between the supply and battery.
AppNote: Extract maximum power from the supply when charging a battery - [Link]