electronics, repairs, service manuals and datasheets discussion community for the repairs professionals and technicians
FAQSearchMembersGroupsRegisterProfilePM'sLogin/Out
Can I use 220V 40W light bulb as resistor to lower voltage?

 
Post new topic   Reply to topic    Electronic equipment repair and service manual search discussion Forum Index -> Electronics General
View previous topic :: View next topic  
Author Message
GrownTree



Joined: 07 Apr 2011
Posts: 1
Location: Canada

PostPosted: Thu Apr 07, 2011 6:35 am    Post subject: Can I use 220V 40W light bulb as resistor to lower voltage? Reply with quote

Can I use an incandescent 220V 40W light bulb as a resistor connected in series with a 110V 15W power supply for my electronic device?

Situation is that I am in a small town in Eastern Europe and I can NOT find a 220V to 110V transformer here.

Any other ideas as to how to lower local 220V to 110V 15Watt without transformer?
_________________
GrownTree
Back to top
View user's profile Send private message Visit poster's website
torbjorn



Joined: 07 Jun 2007
Posts: 370
Location: Sweden

PostPosted: Mon Apr 11, 2011 12:27 pm    Post subject: Reply with quote

It is probably not recommendable to use a light bulb as ballast resistor in this manner, as the resulting voltage will vary depending on the actual power consumption of your power supply.

The best solution would of course be to replace the power supply with one rated for 220 V.
Another makeshift possibility is to use any mains transformer of suitable power rating and with switchable primary for 220 and 110 V as an autotransformer. Connect the 220 V mains across the whole primary winding and take out 110 V between neutral and the 110 V tap.
Back to top
View user's profile Send private message
Flash1940



Joined: 26 May 2011
Posts: 3
Location: Paris, Kentucky

PostPosted: Thu May 26, 2011 6:32 pm    Post subject: Reply with quote

A light bulb is a poor man's constant current source and is NOT a linear resistance. They all have a curve and become higher in resistance the brighter they glow. Would not likely be a very predictable device to use in your application. However....this technique is really handy when working on equipment that is blowing fuses. I think you can visualize how to use it.

Flash
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Electronic equipment repair and service manual search discussion Forum Index -> Electronics General All times are GMT
Page 1 of 1

 
Jump to:  
You can post new topics in this forum
You can reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Електроника София - Service Manuals Free Download - Prikachi - Service Diagrams

Free TV Schematics Download - HARDW.net - Pinout Master - Jabse Search - Jabse.InK  - Pulsator

Connector Pinout Forum - Новини - SnimkiOt.com - безплатен DNS - Whois разузнаване - Poblizo.com : пътешествия