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Tips for making UV lighting using germicidal bulb




I want to erase the UV-EPROMs

I'm thinking of doing a writing experiment on UV-EPROM.

UV-EPROM is a very old, old rewritable ROM.  Data can be written only by electricity, but UV light is required for erasing. The ultraviolet light needs to be irradiated with UV-C, ultraviolet light with a short wavelength of about 235.7nm, which is used for sterilization. Recently, ultraviolet LEDs have become much easier to obtain, but they are not suitable for UV-EPROM erasure because they have a wavelength of about UV-A (315nm or higher).

Normally I use ROM erasers

A device that uses ultraviolet light to erase UV-EPROM data is called a "ROM eraser," and it looks like this machine.

It works as if the heater part of the oven toaster has been replaced by a fluorescent light for sterilization.  I think I irradiated with ultraviolet rays from the top of the ROM for 20 to 30 minutes.

ROM erasers are expensive

ROM erasers are expensive for some reason.  I think it only comes with a sterilizing fluorescent light and a timer, but it's too expensive for my hobby to handle.  Then, the pocket fluorescent light with the fluorescent light of 4W (such as the thing like the one below).

I change the fluorescent light to fluorescent light for 4W sterilization like the one below.

NEC 殺菌ランプ 直管 グロースタータ形 4W GL4

I used to convert it to an ultraviolet radiation device and erase the ROM.

I found a bulb-type UV lamp!

I thought I would make a ROM eraser by buying a 4W fluorescent lamp ballast and a 4W germicidal fluorescent lamp, which is necessary for the ROM eraser.  I was looking for it on the Aliexpress site, and lo and behold, they sell a bulb type germicidal light. Product - DC 10-12V E17 UVC Ultraviolet UV Light Tube Bulb 3W Disinfection Lamp Ozone Sterilization Mites Lights Germicidal Lamp Bulb

Let's take a look at the specs.

Material:Quartz glass
Type:With ozone/Without ozone
Pipe voltage:9.5-13V
UV density of 254nm
30cm,more than 30 Wicm2
Life time:9000h

With a voltage of 10 to 12 V and a power of 3 W, the target 254 nm UV light is emitted.  3W at 10V is about 300mA. Normally, an inverter is required to illuminate an ultraviolet fluorescent lamp, and it is necessary to drive it with high-voltage alternating current.  However, this can generate UV-C ultraviolet rays only with a DC power supply.

How wonderful!

The same can be bought on Amazon. 

除菌器専用電球 E17口金 3W 紫外線電球 2個入り


E17 germicidal light bulb

I bought it immediately

3 weeks from ordering on Aliexpress.  Finally, it arrived. It looks like a fluorescent glow lamp that is a little longer. Since the socket is E17, you can use the glow lamp socket.

There were two types, "No Ozon" and "with Ozon," so I bought two each.  "No Ozon" seems to cut off the wavelength of ultraviolet rays, because it seems that oxygen turns ozone into ozone depending on the wavelength.

Start experiment

UV rays are bad for the eyes, so I put them in a glass bottle to block them.  Then, raise the voltage of the power supply with the goal of 10 to 12V 300mA.

Even if it is 10V or 12V, no ultraviolet light will be emitted.  The filament is slightly reddish. Gradually raise the voltage.

Is it about 16V? The bulb lit up like a flash!

Did an explosion occur inside the light bulb?

It seems that the discharge started at about 16V, the current increased rapidly, and the filament broke because it could not withstand the excessive current.

Use the LED driver

This bulb needs a voltage of about 16V to start discharging, but once the discharge is started, 16V will be an overcurrent. Therefore, once the discharge starts, it seems that the voltage needs to be lowered from 10V to 12V with an upper limit of 300mA. There are electronic components that can easily do such a difficult task, even though it may require difficult control.

It is the LED driver.

Since the maximum current that can be applied to an LED is originally determined, a constant current driver is required to make the LED emit light with maximum brightness.  For a 1W (300mA) LED, choose a 1W (300mA) LED driver. The E17 germicidal bulb this time is also 300mA. It is a 1W LED driver.

LEDドライバ OSMR16-P1231 OptoSupply
Kaito Denshi(海渡電子)

This is the OSMR16-W1231 from ↑. There is also OSMR16-W1213, but please note that the current of 1213 is 3W (1000mA). We need OSMR16-W1231.

Connect this LED driver to E17 socket germicidal bulb.  Turn on the power ~ !!

It glowed nicely.  The voltage is 16V.  When you turn on the power, the filament heats up and begins to discharge.  Thanks to the constant current circuit, excessive current does not flow, and it lights up stably.  As you can see in the video above, the filament glows orange and then brightens up, just like a fluorescent light in the old days. It's a very interesting moment of lighting.

Since there is a constant current driver, any voltage above 16V can be lit stably.  I wonder if the AC adapter, which is easy to get, is going to be 24V.

It's nice.  It is a mystical light. It's an intense UV light, so don't look at it for too long.

Using a 1W LED driver, the E17 germicidal bulb was successfully lit.  I would like to make a ROM eraser using this bulb.  If you want to buy at Aliexpress, click here Product - DC 10-12V E17 UVC Ultraviolet UV Light Tube Bulb 3W Disinfection Lamp Ozone Sterilization Mites Lights Germicidal Lamp Bulb

On Amazon, click here.

除菌器専用電球 E17口金 3W 紫外線電球 2個入り

Don't forget the 1W LED driver.

LEDドライバ OSMR16-P1231 OptoSupply
Kaito Denshi(海渡電子)

The next page is here ↓↓↓.  Make a ROM writer board.