Vintage Philips QB 3.5/750 Tetrode Vacuum Tube Print E-mail
Thursday, 26 May 2011 08:57
Some time ago I was given a vintage Philips QB 3.5/750 Tetrode vacuum tube. It's spent most of that time hiding away in a box. Why? Perhaps I was keeping it for "special" but as time has shown, special never comes and it's time to pull out the things that I have had put away and enjoy them now - no more waiting for "special" to arrive.

The box that the tube was in was somewhat tattered - not great for sitting on the shelf. So I started about designing a display for it. First job was to see if I could find the data sheet - to get the correct pin spacings. Google returned a few results and only after a few minutes looking I had a copy of the data sheet.

Knowing the over-all size, I headed off to Rahul's great online box maker website and generated a box. I then dumped the resulting PDF file into CorelDRAW and the end result is this:

Click to embiggen

This Philips QB 3.5/750 Tetrode vacuum tube is designed for use as a High Frequency amplifier and oscillator. It has an output of around 750 watts!

This is a big tube - Really big! The tube is 145mm high x 87mm wide.

Here's a 1000w amp - it has two :)

More photos after the jump...
532nm Green Laser Pointer Print E-mail
Tuesday, 09 November 2010 10:41
After the success of my last laser pointer, I thought I would make another. I ordered a 532nm 75mw green laser diode off ebay. Since this draws more power than the 405nm diode I purchased last time, I decided to run it off 4 AA batteries, wired to produce 3v. Turned from a length of aluminium tube with the heat-sink and base cap made from solid aluminium rod. Everything is held together with some grub screws.

Green Laser Pointer
Click to Embiggen

This took me a couple of evenings work on the lathe. A black momentary button located near the front fires up the laser. And yes, I've been driving my cat insane ;)

Green Laser Pointer
Click to Embiggen
405nm Laser Pointer Print E-mail
Monday, 06 September 2010 21:47
Changes to Australian import laws a couple of years ago means that we can no longer import laser pointers - however this ban does not extend to laser diodes or modules. I purchased a 405nm laser module off ebay recently and decided that I needed a housing for it. 405nm was advertised as Blue/Violet - it's a nice colour, but more towards the UV end of the spectrum.

A visit to Jaycar on the weekend set me up with a AAA battery holder and a push-button and an afternoon on the lathe with some Aluminium turned out this:

Aluminium Laser Pointer - Front

Aluminium Laser Pointer - Side    Aluminium Laser Pointer - Back
Click to Embiggen

I'm happy with the result and it looks a little like a light-saber!
Retro Atari 2600 Cartridges Print E-mail
Monday, 15 February 2010 01:47
What was under your Christmas tree in 1977 - That hand knitted sweater from grandma? A tub of Slime? Orthello? or how about a skateboard? Or did you get an Atari Video Computer System?? In 1977 I was 6 - I don't remember what I got that Christmas but I do know it wasn't a 2600.... That I had to buy myself many years later.

Released in October 1977, the Atari VCS (renamed to Atari 2600 after the release of the 5200), went on to sell 30,000,000 units world-wide. Although released a year after the Fairchild Channel F, it marked the start of the home video game revolution and kept kids glued to the telly ever since.

Atari 2600 - Atari - Asteroids Atari 2600 - Atari - Pac-Man Atari 2600 - Atari - Space Invaders Atari 2600 - Atari - Defender Atari 2600 - Atari - Missile Command Atari 2600 - Atari - Berzerk
Click to embiggen

You can take a look at all 154 cartridges on my Flickr set
Handheld Games of the 1980's Print E-mail
Tuesday, 09 February 2010 06:41
Back in the 80's, in a time long before the DSi and PSP, gamers who wanted to entertain themselves while in the back of mum & dad's car were restricted to playing just one game! Yes, that's right - JUST ONE GAME!!! I know that may seem just completely outside the realms of sensibility, but it's true. And to prove it, here's one of those games...

Tronica - Power Boat Racing - MG-231
Click to Embiggen

A whole bunch more can be seen in my Flickr set.
Digital Storage Oscilloscope Print E-mail
Wednesday, 24 June 2009 09:34
It's been a while since I've given my soldering iron a serious workout, but when I saw the Digital Storage Oscilloscope kit online at Seeed Studio the other week I figured I'd blow off the dust and put it to work!

The kit comprises of both front and back panels, PCB (with microprocessor pre-soldered) and a pile of SMT & Through-hole parts.

Digital Storage Oscilloscope

Completed kit!

This is a great kit that you can have up and running in a couple of hours and a very handy piece of test equipment, too.
7 Segment Digital Clock Print E-mail
Wednesday, 17 October 2007 01:17

This is my first non-nixie clock.  Built using the schematic and code provided by José Pino .

7 Segment Clock

José has provided pre-compiled HEX code suitable for the PIC16F628 (I'm using a PIC16F628A without any problems) Code is also supplied for the PIC16F84. The layout is very simple and keeps good time - gaining only a few seconds after a couple of weeks running.  The first photo shows the complete clock (two surface mount capacitors are mounted under the board, as well as the two 10k pull-down resistors from pins 6 & 7). 

Happy Birthday Aussie TV! Print E-mail
Sunday, 17 September 2006 15:00

ImageThis week, Australian TV turns 50!!

The development of Television started more than 130 years ago with the discovery of Selenium's photoconductive properties by Willoughy Smith in 1873.  Over time, inventers such as John Logie Baird and Philo Taylor Farnsworth both demonstrated different ways of transmitting an image from one location to another.

John Logie Baird, in 1926, demonstrated what is considered to be the first true television system by electrically transmitting moving pictures.  Just two years later, television broadcasts begun in America, followed by Britian in 1936.

Just a short 30 years after John's demonstration, Bruce Gyngell launched television in Australia with the now famous words "Good evening and welcome to television".  This first official broadcast coming from TCN Sydney, 16th Semtember, 1956.

Over the next 15 years, Television was introduced around the nation:

    NSW, Queensland and Victoria - 1956
    South Australia - 1959
    Tasmania - 1960
    ACT - 1962
    Northern Territory - 1971

From Valves to Diodes, From Black and White to Colour, from Analog to Digital - the last 50 years has been an incredible journey.

GIANT Clocks? Neat Site! Print E-mail
Tuesday, 28 March 2006 14:35

Just how big does a clock have to be to be a GIANT clock?


The Unofficial Registry of Giant Digital Clocks has that answered.  Go - check it out :)

Weird LEDs Print E-mail
Wednesday, 22 March 2006 17:23

I don't know if anyone has noticed, but I have a slight addiction to shiney things...  So, anyhow, the nice folk at LEDSales were happy to oblige and supplied me with some neat LEDs for a very resonable price.


These are Russian-made side-view LEDs and are about 2mm big.  They have a rated current of around 6ma.  I am running the one in the photo at about 8ma. 


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