Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => The Newcomer's Forum => Topic started by: saturated on December 09, 2024, 11:49:02 PM

Title: I'm learning maybe pay attention to watts
Post by: saturated on December 09, 2024, 11:49:02 PM
So I got this bag of fuses (1A 250V) and they looked good but I thought hey why not check one of these things  :tu:

So I came up with a plan....put the fuse in circuit with a 10 ohm fuse and run it up to 10v
while keeping an eye on it.

Well I started at 7.9v and the smoke show started quickly
IMG_20241209_223352792 (1).jpg

So I did some calculations wow I was going for one amp I never dreamed I would be cranking out some watts
IMG_20241209_223337994 (1).jpg

That resistor is like a quarter or half watt.
 :loco

Btw the fuse survived  :dbtu:

But as I type this now it makes sense why I see these big ceramic wire wound ? resistors and they are low resistance

 8|
 
Title: Re: I'm learning maybe pay attention to watts
Post by: saturated on December 10, 2024, 01:56:33 PM
I'm back with a five watt two ohm resistor

Holding steady at 0.5A

IMG_20241210_123810572_HDR.jpg

IMG_20241210_124413993_HDR.jpg

Now on to 0.75A
 :loco
IMG_20241210_124438223_HDR.jpg

And feeling particularly bold 0.89A (eek xP )

IMG_20241210_124504796_HDR.jpg

To boldly go....

Scotty_zpsaed6c853.jpg

Title: Re: I'm learning maybe pay attention to watts
Post by: Miyagi_83 on December 10, 2024, 02:01:53 PM
I really enjoy your sense of humor, man :)
Title: Re: I'm learning maybe pay attention to watts
Post by: saturated on December 10, 2024, 02:21:49 PM
The experiment has reached a conclusion

The one amp fuse opened at exactly 3v

1.5 amp  :tu:

I guess

Title: Re: I'm learning maybe pay attention to watts
Post by: g1 on December 10, 2024, 04:50:08 PM
The datasheet for the exact model of fuse will tell you how much over current rating it can go before it blows (and for how long).
Title: Re: I'm learning maybe pay attention to watts
Post by: saturated on December 14, 2024, 09:36:34 PM
Does current have different speeds ?

Maybe that's what watts is all about ?  :loco

Seems like current going through a low voltage drop would be slower than current going through a large voltage drop.

But then a bigger voltage drop would be bigger current.... through a bigger voltage ⚡ drop...seems like things could get out of hand in a hurry.


Title: Re: I'm learning maybe pay attention to watts
Post by: J M Fahey on December 14, 2024, 11:54:20 PM
Quote from: saturated on December 14, 2024, 09:36:34 PMDoes current have different speeds ?

Maybe that's what watts is all about ?  :loco

Seems like current going through a low voltage drop would be slower than current going through a large voltage drop.
No, current speed is the speed of light.

In our Audio world, instantaneous.

Current speed becomes relevant at very high Radio frequencies, think VHF and UHF

Back to fuses: they blow at higher or lower speed because it takes some time to heat wire enough to melt and open the circuit.

In your case, 1 Ampere rating means fuse will pass that current indefinitely with no problems.

As you go higher, it will eventually blow, faster and faster as you increase current.

As mentioned above, fuse datasheets show that.

(https://i.postimg.cc/XJC36LqV/Fuse-blow.gif)

Title: Re: I'm learning maybe pay attention to watts
Post by: g1 on December 15, 2024, 02:31:46 PM
Generally, there are fast blow and slow blow fuses, for the reasons JM stated above.  But even among each type, the speeds vary, and will be shown in the datasheets.