The identification for the Amidon toroids consists of one or two letters (T=toroid and FT=ferrite toroid), followed by a number (for ex. T50), which represents the outer diameter dimension expressed in 0,1 inches, followed by a separation mark (dash, dot, stroke), followed by another number indicating the frequency mixture and the frequency range at which it would be recommended to use the toroid.
It should be taken in account that a toroid with a X declared frequency will be able to operate with fairly good performances even at 10 times higher frequencies and only the A factor will decrease.
The iron powder toroids are colored according to their mixture; the first color covers three sides and the second color the remaining side.
Simple software to calculate the air core coils, the most widely used in RF circuits and may use the software to determine the data to build a coil, knowing that the inductance of this coil. The software will give the result of how many turns will be required to achieve certain inductance value, and provides the wire diameter … In addition has a table with wires AWG mm thick.
Radu Motisan writes:
Here is an electric fence, perimeter protection circuit, designed to run on batteries, and provide configurable pulses of up to 20KV, to protect a tent perimeter against bears or other animals, out in the wild.
The high voltage generated is not dangerous because of the low current (and power), but it will produce intense pain.
Electric Fence – 20KV pulses for perimeter defense – [Link]
Johan von Konow writes:
This post is the last of three and describes the software needed to build a web controlled home automation center. The previous two describes how to add a serial interface to a router and how to build a microprocessor lab board.
- Software for the router (OpenWrt)
- Software for the web server (html and CGI)
- Software for the lab board (PIC16F628 assembler)
- Protocol for serial communication between router and lab board
- Protocol for 433MHz radio (and html generation tools)
Web controlled home automation – [Link]
The temperature switch IC inverts the output according to the detected temperature, enabling a simple circuit configuration ideal for reducing costs and space in a system.
In a temperature switch that is configured using a thermistor, a comparison circuit is required downstream. However, this circuit is not required in SII’s temperature switch IC because the IC inverts the output when the detected temperature reaches a preset value. This makes the IC ideal for reducing costs and saving space in the customer’s system.
In the temperature switch ICs, the output is inverted when the temperature exceeds the set value.
The following temperature switch ICs are available: a latch type that maintains an inverted state (latch) to prevent an unstable output at the detected temperature and a hysteresis type that releases the inverted state when the temperature decreases to the set value.
S-5840B / S-5841 – Temperature Switch ICs – [Link]
Sam Byford writes:
NEC has been developing its organic radical battery (ORB) technology for a while, and today it unveiled the latest iteration. The newest ORB is a 0.3mm (0.012 inch) flexible battery that’s designed to fit into integrated circuit (IC) cards, commonly used for public transport payment, credit cards, and suchlike. Standard IC cards are 0.73mm thick, meaning the addition of a battery shouldn’t prove too taxing on your wallet. Furthermore, the battery can be printed directly onto the IC card as part of the manufacturing process, and the surrounding 0.05mm polymer film can incorporate circuit boards with small components like antennas.
0.3mm thin ‘organic radical battery’ can be printed – [Link]
Derek Wolfe writes:
This is an all-in-one module for Atmel ATtiny24/44/84 8-bit microcontrollers and all necessary components to run them. Having a microcontroller module is nice because it reduces the amount of redundant design in projects using microcontrollers. You only need to provide 5V power and connect to the I/O lines to make a prototype microcontroller circuit. This design easily connects to a breadboard or a subcircuit with header pins and can also be wired directly for a permanent installation. Subcircuit design is greatly simplified by a modular approach because there are no traces blocking the way to the microcontroller pins. All traces on the microcontroller module are essentially on a different level making connections much easier.
ATtiny24/44/84 Mini Board – [Link]
Sorry for the lack of photos in this article, but we didn’t think about it being worth reporting until after it had all happened. Infact, we were concerned about retaining any evidence of the events. Inspired by the many toaster-oven reflow projects floating around the Internet, we set out to acquire the power to solder all those tiny SMD components ourselves. Toaster ovens aren’t that common in the UK and we were aiming for the lowest cost possible, so we hit ebay in search of a bargain. A very cheap Black and Decker Toast-R-Oven was on offer. The description was “only used a few times”, and the grainy photos showed an indeterminate “foreign” plug with an adaptor. Now, we aren’t generally in the habit of assuming that “some bloke on ebay” must know what he’s doing with electricals, but with the auction starting at £5 (and not going up a huge amount from there by the end) it seemed like a good idea.
Engineering of a reflow oven controller – [Link]
LCD in this picture has 2×16 characters, so in quick way horizontal bar could have 16 steps resolution, but it’s not enough. Each character is formed from 5×8 pixels. Every character can be sliced in to 5 pieces. After that we can have 5*16 = 80 steps. First step is to create 5 custom characters. More about createChar() please read at arduino.cc.
Arduino LCD horizontal progress bar using custom characters – [Link]
Radu Motisan writes:
I’ve just completed the first tests of a new challenging project, a pulsed discharge micro spot welder and cutter tool. It stores energy into a huge capacitor bank, and discharges it via two electrodes in the given target, regularly metal foils/sheets. The logic and the precise timing (of the order of micro-seconds) is controlled by an AtMEGA16-16PU microcontroller running at 16MHz. It can be used for spot welding and for plasma cutting.
Capacitor Discharge Microspot Welder / Cutter – [Link]
Johan von Konow writes:
A miniature breakout board for rapid development of microprocessor projects
- ICSP connector for quick programming and power (PICkit compatible)
- All pins available on standard .1” pin headers
- Single sided PCB (easy to manufacture)
- 4 debug led’s
- 1 generic switch
- Connector for serial communication
- Power led
- On board crystal with decoupling caps
- Miniature size
Ultimate PIC16F628/627 breakout board – [Link]