Exactly, I have 200 and 300 watt bulbs. Im going to make a jig with 4 bulbs of different values and be able to switch them in and out to get whatever value I need.
100 W lamp draws 830 mA, or .83A, not .83mA. Similarly, the 40 W lamp draws 330 mA, 0r .33A, not .33mA. Other than that minor thing, the information you gave is very good. I’ve also encountered folks who tried to use an LED as a current limiter in a dim bulb tester.
The term "dim bulb tester" was coined before LED light bulbs were a thing. These newbies must realize it only works for the old incandescent bulbs. You explained very well Fred. You can still find old bulbs at places like Goodwill in their original cardboard sleeve boxes. I got a couple of 40 and 60 watts ones there a year ago. Steve from IL
Yeah, the tungsten filament is an integral part of the dim bulb tester and someone just starting out would easily make that mistake just seeing one and using "modern" parts to make it. Old incandescent bulbs that are good is one more thing to save when you find one.
I'm using an old camera exposure light that's 300 watts and a variac in series. I can see the filament because it's clear glass, im used to it and it's good for TVs. It will glow if the caps are bad even on a little radio. I also don't believe in reforming much if the caps don't come around during a slow turn of the variac there getting changed.
Why not use a 250W incandescent bulb such as one used in a brooding lamp. It has a very low resistance and so there’s a low voltage drop across the bulb and there’s no dim bulb glow during normal operation (i.e. not shorted).
Hi and thanks for jumping in. You could use any wattage bulb but the way I was taught was to match or come close to the wattage of the unit under test. By doing that your watching the response of the unit during power up as it also absorbs the rush of current on caps that probably have not been powered up in a long time. So the idea is not just to look for a shorted transformer, capacitor or other parts the bulb along with a variac allows the unit under test to come back on without being shocked with a rush of current. It's kind of like waking up to soft music rather than an alarm that sounds like a fire alarm. I hope this answered your question, I'm not an engineer, just an explanation based on my training as an electronic technician.
Good information Fred- I like to keep my high draw incandescents in hand for appliance testing. 😃👍
Exactly, I have 200 and 300 watt bulbs. Im going to make a jig with 4 bulbs of different values and be able to switch them in and out to get whatever value I need.
100 W lamp draws 830 mA, or .83A, not .83mA. Similarly, the 40 W lamp draws 330 mA, 0r .33A, not .33mA. Other than that minor thing, the information you gave is very good. I’ve also encountered folks who tried to use an LED as a current limiter in a dim bulb tester.
Thanks, LOL, I had that in my head and said something else.
Yup. Happens to me all the time.
The term "dim bulb tester" was coined before LED light bulbs were a thing. These newbies must realize it only works for
the old incandescent bulbs. You explained very well Fred. You can still find old bulbs at places like Goodwill in their
original cardboard sleeve boxes. I got a couple of 40 and 60 watts ones there a year ago. Steve from IL
I have a good stock of 40, 60, 100 and 200 watt bulbs. I think it's time we find a replacement for the dim bulb tester.
A must have if you're working on old Tube Radios! I have a few spare incandescent bulbs. I won't use modern LED lights etc, not good!
Yeah, the tungsten filament is an integral part of the dim bulb tester and someone just starting out would easily make that mistake just seeing one and using "modern" parts to make it. Old incandescent bulbs that are good is one more thing to save when you find one.
Exactly, you need to have those old bulbs.
I'm using an old camera exposure light that's 300 watts and a variac in series. I can see the filament because it's clear glass, im used to it and it's good for TVs. It will glow if the caps are bad even on a little radio. I also don't believe in reforming much if the caps don't come around during a slow turn of the variac there getting changed.
Thanks for sharing your experience!
Why not use a 250W incandescent bulb such as one used in a brooding lamp. It has a very low resistance and so there’s a low voltage drop across the bulb and there’s no dim bulb glow during normal operation (i.e. not shorted).
Hi and thanks for jumping in. You could use any wattage bulb but the way I was taught was to match or come close to the wattage of the unit under test. By doing that your watching the response of the unit during power up as it also absorbs the rush of current on caps that probably have not been powered up in a long time. So the idea is not just to look for a shorted transformer, capacitor or other parts the bulb along with a variac allows the unit under test to come back on without being shocked with a rush of current.
It's kind of like waking up to soft music rather than an alarm that sounds like a fire alarm.
I hope this answered your question, I'm not an engineer, just an explanation based on my training as an electronic technician.