simple LED or light bulb flasher

I want to design a simple LED or light bulb flasher. I found one which consists of 1MΩ resistor and 0.5µf capacitor. A neon light will be connected in parallel with the capacitor. The DC voltage is 90V. I couldn't get it to work. The capacitor is supposed to be charged by the DC and discharged by the bulb. But it didn't happen. I noticed that voltage going to the capacitor is a lot less than 90V when resistor is connected. Something is wired wrong. If you even have a multisim of the circuit, I would really appreciate it.

Thank you.

Make sure that you use high voltage capacitor, a 250Vdc rated cap will be a good choice ..

**broken link removed**
**broken link removed**

Regards,
IanP

can I use LED instead of the neon bulb and the circuit will still work?

I know a very simple idea, you can use the Neon lamp stater to make a 220V bulb flasher

Connect it in series to the lamp (or to as many bulps as you want all in series)

In other words, the circuit is simply a fluorescent lamp starter wired in series with a normal light bulb. The starter kicks in and out on a (sort of) random basis causing the lightbulb to flash on and off in a flickering sort of way.

Basically you can just wire a fluorescent light starter just simply in series with a normal light bulb but going this simpel way has it's risks. If somebody screws in too powerful light bulb you will burn out the starter (propably fire danger). u can simply use a fuse in series to protect the circuit against serious overload or short circuits.

I didn't try it in fact, but it will work pretty well..

Enjoy
I hope that it will help
Best Wishes
Ahmad,
Ahmad,

kae_jolie said:

I want to design a simple LED or light bulb flasher. I found one which consists of 1MΩ resistor and 0.5µf capacitor. A neon light will be connected in parallel with the capacitor. The DC voltage is 90V. I couldn't get it to work. The capacitor is supposed to be charged by the DC and discharged by the bulb. But it didn't happen. I noticed that voltage going to the capacitor is a lot less than 90V when resistor is connected. Something is wired wrong. If you even have a multisim of the circuit, I would really appreciate it.

Thank you.

Click to expand...

Hi, try to reduce the 1MΩ resistor to as low as 100-150kΩ and test again. If it still not working, you may have a neon bulb with already a built in resistor?
Notice the half wave rectifier diode in IanP first link, have you included?
Finally the input resistance of your voltage meter is not shunting the neon voltage down? If all else fails try the neon lit on without any blinker circuit by feeding directly through a diode with a Variac (variable rotary autotransformer).

rgds, unkarc

kae_jolie said:

can I use LED instead of the neon bulb and the circuit will still work?

Click to expand...

No, the original circuit for neon flasher is based on the negative volt-ampere characteristic curve of the neon bulb. At LED, this curve is positive.

nguyennam