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 Dim bulb tester
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 Return to top of page · Post #: 1 · Written at 9:05:33 AM on 18 August 2020.
Bowler's Gravatar
 Location: Bongaree, QLD
 Member since 26 October 2018
 Member #: 2308
 Postcount: 56

Hi All, I am contemplating the construction of a dim bulb tester. What sort of a bulb is suitable now there are no more incandescent types. ?Bowler.

 Return to top of page · Post #: 2 · Written at 9:25:52 AM on 18 August 2020.
Trobbins's avatar
 Location: Melbourne, VIC
 Member since 11 July 2012
 Member #: 1179
 Postcount: 56

Perhaps build a collection of old incandescents. Look in old garage sheds, or contact the company that replaces old lights with LED lights, or ask around for friends to look in the their 'spares' cupboard, or back rooms.

 Return to top of page · Post #: 3 · Written at 9:42:12 AM on 18 August 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2109

For working on TVs, bathroom heat lamps work well.

Maybe equip yourself with a bag of LED lamps and walk down the street, crying

"New lamps for old!"

 Return to top of page · Post #: 4 · Written at 9:54:56 AM on 18 August 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4749

If you look around you may score some, however I do not use one and there has never been one here in decades.

The stupidity is that a light bulb may put out more heat than light, for the benefit of pensioners. I would wager that it is cheaper to make & almost 100% recyclable compared to what's in an electronic type and are a clean load.

If I need to; I use a "Variac" aka Slide transformer. In this there are risks with both. Depending on the situation I tend to use an isolation transformer fitted with fuses both sides and a "Kill" Switch.

Not trying to be a "Kill Joy" Do be aware that with a Slide transformer it is common to the mains both sides. If the output falls below 130 volts AC: You will have no protection from the 30mA RCD's (earth leakage trips) on the mains. I have deliberately plugged in an RCD tester to prove this. I would expect this with some globes.

Running valves at too low a voltage can "poison" the cathodes of some valves.

Plugging in an an unknown to you, electrical device to see if it works, without inspecting it. Especially an old radio left sitting for ages, is asking for trouble.

The best you may do are globes for stoves sewing machines etc. which are low wattage and perhaps halogen: Beware many are also Low voltage.


 Return to top of page · Post #: 5 · Written at 11:43:54 AM on 18 August 2020.
Johnny's avatar
 Location: Hobart, TAS
 Member since 31 July 2016
 Member #: 1959
 Postcount: 513

Marc's comments confuse me greatly.
I have used a "dim bulb" tester for probably 40 odd years, in my full-time profession in the electronic service game.
I also have variacs isolation transformers and any amount of test equipment.
But the "dim bulb" tester is always in circuit with anything I'm working on.(including an isolationTX).
It incorporates two standard bayonet sockets, so that I can use for example 2X100 Watt globes for TV work, or a single 40 or 60 Watt for reforming caps etc.
And Marc, if you were working on a high current switch mode power supply, its the only way to go.

 Return to top of page · Post #: 6 · Written at 1:55:41 PM on 18 August 2020.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4749

I have only worked on one high current switch mode recently & tend to not have to deal with them that often. Most of what I deal with is old valve radio stuff & rarely valve TV. I did work in OH&S in Industry & it is amazing what can be achieved, including what one thought impossible.

There are quite a few things that have some savage startup current which is why we see "slo blow" fuses & "soft starters" in some stuff. However, the only Valve radios with anything like a frightening start-up surge I have dealt with are the larger American types with 18 &16 Valves & four in push pull. One actually has push pull driving push pull.

There is a post on the US Forum that may be of interest



 Return to top of page · Post #: 7 · Written at 4:38:46 PM on 18 August 2020.
Vintage Pete's avatar
 Location: Albury, NSW
 Member since 1 May 2016
 Member #: 1919
 Postcount: 2047

For a TV or Radio?
You can get bulbs that will work for a TV at Bunnings...if you need lower Watts for a Radio ,They can still be bought off eBay.
That's how I made mine...I have a set up for TVs...

PS its set up for TVs using 75 watt small Reflector "" flood "' But they have them in 40w too so you just change it . They still sell many different wattages so just chop and change for what you need ,radio ,Tv Etc etc

 Return to top of page · Post #: 8 · Written at 2:21:01 AM on 19 August 2020.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 1817

There are plenty of incandescent bulbs available on ebay

 Return to top of page · Post #: 9 · Written at 3:30:10 AM on 19 August 2020.
Robbbert's avatar
 Location: Hill Top, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 1737

I imagine you could probably still get those small 25W globes that could be used in fridges etc.

Put 4 in parallel to simulate a 100W globe. Remove one to simulate 75W, etc.

 Return to top of page · Post #: 10 · Written at 7:25:25 AM on 19 August 2020.
Fred Lever's Gravatar
 Location: Toongabbie, NSW
 Member since 19 November 2015
 Member #: 1828
 Postcount: 1049

Yep Ebay has plenty of suppliers.
I have bought recentlyfrom "bestpriceinsydney" 10 off B22 240v 100w frosted BC base, $30.
The correct bulbs arrived.
Two other suppliers sent Edison Screw bulbs and denied doing so! Obviously stuck with a warehouse full of ES nobody wants and hoped I would cop it.

 Return to top of page · Post #: 11 · Written at 8:22:21 AM on 19 August 2020.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 1073

"I imagine you could probably still get those small 25W globes that could be used in fridges etc."

I replaced an oven light some months ago. There were 15 and 25w versions at the time. These were small edison screw.

Refrigerator light done a couple of years ago was standard edison screw, and microwave and range hood lights small edison screw. Could probably get these through parts suppliers servicemen use if the large green place hasn't got them.

So incandescent still around. Ovens especially couldn't have anything else when the light is right in the oven.

(By the way these are rated to handle the temperature so you can't use just any light, it should say "oven light", otherwise they go black very quickly. Doesn't matter for dim bulb tester of course.)

New refrigerator bought last year has LED lighting, so eventually even these light will disappear.

One particular microwave (I think Panasonic) wasn't the standard small edison screw thread but a little larger, so watch out, but don't suppose anyone would go that way.

 Return to top of page · Post #: 12 · Written at 12:47:31 PM on 19 August 2020.
Destino's Gravatar
 Location: Bells Beach, VIC
 Member since 20 July 2020
 Member #: 2428
 Postcount: 39

You can still buy some incandescent bulbs at Bunnings. They are normally the flood light type of PAR38.


They have an Edison screw mount.

 Return to top of page · Post #: 13 · Written at 6:49:22 PM on 19 August 2020.
GTC's avatar
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6406

Apropos of the subject of incandescent bulbs, coincidentally I have been perusing in Silicon Chip April 2007 the Rodney Champness design for a 'Super Crystal Set'. The cover of that issue has in large letters GOVT TO BAN INCANDESCENT LAMPS? They're dreamin!

Included on page 11 is a copy of the Media Release put out by Turnbull on 20 Feb 2007 with the heading: World First! Australia slashes greenhouse gases from inefficient lighting.

Extract from the Publisher’s Letter by Leo Simpson:

QUOTE: As a proportion of domestic power consumption, lighting is quite small. If we halve the power used by domestic lighting, it will have very little effect on our overall power bills and, by extension, on greenhouse emissions. For those that don’t already know, the major power use in homes is for heating, cooling and cooking. Any reduction in domestic power use due to the proposed ban on incandescent lamps will be easily swamped by the increasing take-up of air conditioning and plasma TVs.

Another factor to be considered is that most domestic lighting use is at night. That might seem blindingly obvious but the government has apparently not recognised why it might be important. The reason that it is important is that most power usage night is merely using the “spinning reserve” of our base-load power stations. You could switch all the lights off (if that was possible) and the base-load power stations would still be spinning away, using just as much coal.

On page 10 Leo writes about the various evils of CFLs and the fact that the government's proposal took no heed of the vast variety of incandescent bulbs in use at the time, apart from special need areas such as medical lighting and ovens.

 Return to top of page · Post #: 14 · Written at 7:32:17 PM on 19 August 2020.
Brad's avatar
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6851

To be honest I am glad we went the way we did with incandescent globes. They are ultimately only 8% efficient and whilst they arguably put out the best quality warm white light of any of the available light sources, in the last few years they were available they were of poor quality and as mentioned, most of the energy used was given off as heat. In a LED globe, the 8 watts of consumption is effectively all given off as light, saving the other 92 watts for use in a heating or cooling appliance, whilst the 8 watt LED globe gives off the same light as a 100 watt incandescent one.

Yes, it is true that for an individual residence, the cost difference isn't that much but consider the power savings across a suburb, freeing up capacity for other uses. At the time the ban on standard incandescent globes was proposed I wrote to John Howard to given him every encouragement to go ahead with it and also suggested that low voltage halogen globes were a huge energy consumer too, which they are when one considers the way people install downlights.

The Editor Emeritus of Silicon Chip will no doubt throw his hands up in horror at the statements above but that is just how it is. The irony is that in recent years he boasted about how he replaced all the fluoro lighting at SC HQ with LEDs and the cost savings involved, not to mention that he'd never have to get on a ladder again to change the old light globes!

A valve a day keeps the transistor away...

 Return to top of page · Post #: 15 · Written at 7:41:05 PM on 19 August 2020.
GTC's avatar
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6406

Still burning incandescents here (while stocks last), so I'm not saving the planet ... nor the whales for that matter.

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