Search found 21 matches

by Oxford
Wed Jun 09, 2010 1:01 pm
Forum: General Discussion
Topic: 12V TO 6V CONVERTER CIRCUIT
Replies: 2
Views: 654

12V TO 6V CONVERTER CIRCUIT

I have yet to find anything except the desire to sell me one. I find converter and inverter used interchangeably in this context. This seems to be a topic that Forrest Mims didn't touch on . Can someone provide a link to a circuit describing how to drop the voltage while controling the amp output wi...
by Oxford
Thu Dec 11, 2008 7:50 am
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

tip3055 npn transistor thru put

This my final posting in this subject. The drawing (JPEG) is intended to show a tested circuit with the parts suggested by those that helped me on this forum achieve a functioning project. The 2K resistor should be reduced in size to about 1K in order to have the reference pot work more in the mid r...
by Oxford
Fri Nov 21, 2008 5:04 pm
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

Ordering IRF3704 from mouser
Roger
by Oxford
Fri Nov 21, 2008 4:05 pm
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

I was posting too maany replys to prove that I had learned how to upload an image. I did not mean that I wasn't getting attention. Sorry. The Darlington is out. Of course the MOSFET drive the heaters but it does get hotter than the darlington and quick. It sound like a MOSFET with better ratings for...
by Oxford
Fri Nov 21, 2008 1:32 pm
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

Looks like I'm talking to myself but actually I'm going to post a JPEG image as suggested earlier to describe my efforts at assembling a percent time on controller. http://www.postimage.org/Pq1ApJ19.jpg Apparently I have to use the MOSFET to turn on the Darlington instead of vice versa. The darlingt...
by Oxford
Fri Nov 21, 2008 8:14 am
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

A new IRF510 MOSFET met all the tests: battery voltage 12.01 volts across the 10 ohm in parallel heaters 10.72 volts across the source and drain 1.19 I also took out the V+ hook up to the gate and pulsed the MOSFET from a 2N2222 and observed 1.9 amps being drawn thru the heaters. The Mosfet can diss...
by Oxford
Fri Nov 21, 2008 4:54 am
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

Firstly, return the FET gate to ground (gate and source
now shorted) and the LED should not light. If it does
your FET is damaged and must be replaced with a
fresh one.
It lights at this point and must be replaced. I'll report back later.

Roger
by Oxford
Thu Nov 20, 2008 3:58 pm
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

I have the LM555CN pulsing a 2n2222 transistor with proper biasing. The transistor output can be placed on the base of a TIP120 Darlington or on the gate of an IRF510 power MOSFET Transistor and each will drive an LED. Neither of the last two items will turn on fully because I cannot observe the 2.1...
by Oxford
Sun Nov 16, 2008 4:52 pm
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

Much of what has been suggested is sinking in now.

Transistor biasing has never been need in my other very simple efforts, but it surely is needed now. I just printed out two good sources.
I will cool it until I get a grasp on biasing as away to think about using transistors effectively.

Roger
by Oxford
Sat Nov 15, 2008 3:53 pm
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

I do not have experience on this site to attach / send a bit map drawing.

Any help on this topic would be appreciated.

Roger

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by Oxford
Sat Nov 15, 2008 3:36 pm
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

I just realized that I have no idea how to send a bit map drawing to this site.
FAQ 's didn't help.
Someone please send a drawing to help me understand how to do it.

Roger
by Oxford
Sat Nov 15, 2008 5:47 am
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

I have the IRF510 MOSFET on the board with 12V battery power and when pulsed by the 555 it drives the led on and off with full range adjustment beautifully.
I will hook up the load later. I gota go out.

Thanks for the support,

Roger
by Oxford
Fri Nov 14, 2008 1:10 pm
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

Ok, I will try the mosfet again on battery power. It didn't work at all on 2.5 amps supply (12 v) the first time.
A drawing (BMP) later when it works.

Roger
by Oxford
Fri Nov 14, 2008 11:43 am
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

Bigglez, I am running two 10 ohm cartridge heaters in parallel requiring 2.12 amps. The bipolar transistor is cooking the air around it but I only run it briefly until I get the bugs out. A heat sink is mandatory. You just said that completely on disapates less heat??? When I get there, fully on wil...
by Oxford
Fri Nov 14, 2008 11:33 am
Forum: General Discussion
Topic: TIP3055 NPN transistor thru put
Replies: 40
Views: 6960

TIP3055 NPN transistor thru put

You were exactly right about base current. Initially I used the bench power supply which is +12 @2.5 amps and got the same .7 amp turn on that I was getting from the pulses of the 555 timer. When I used the 12 v battery direct to the gate I got 1.9 amps +thru the transistor. Very shortly It will be ...