Recent content by SMD1990

My multimeter's diode testing mode shows the drop between the base and emitter as 0.55 V. The short-circuit current of the AA should be less than the transistor's maximum rating. Besides, should not the limited base current keep the collector current limited to well below the maximums? If...

Hello. As the title says, I need some help in getting a transistor to amplify a current. I have a TIP120, whose DC gain is specified as 1000. I am applying a positive voltage of about 0.6 V to the base. The current is around 10 μA. I have the positive side of a AA cell connected to the...

Zinc reacts with sulfuric acid to produce zinc sulfate and hydrogen. But then, when electrowinning zinc, this is reversed, with zinc deposited on the cathode, oxygen evolved at the anode, and sulfuric acid also produced. So why does the sulfuric acid not immediately react with the zinc...

I will admit that I still have a bit of trouble when it comes to reading the table of standard electrode potentials. (Though, I do think my understanding is improving.) However, unless I am mistaken, should not Daniell cells (zinc anode, copper cathode, sulfate solutions) not rechargeable...

Off and on, I have been messing with making a little transformer. My first attempt was last winter. They never seem to really work very well. Is there any sort of rule regarding the amp-turns needed around a core with a particular permeability? My earliest attempts used a straight rod...

Does electrolyzing molten aluminum hydroxide yield aluminum, water, and oxygen? The equation can be balanced so that it does, but does this really happen?

Oh, okay. Now I understand. Thank you for explaining!

Considering the bottle remains basically unchanged, the initial and final volumes are the same, no? Or, does "volume" refer to the amount of air, irrespective of its confinement within a fixed "volume"? Ever heard of a water rocket? They typically use pressures of 75 to 150 psi, and bottles...

I have read that soda bottles (plastic) can withstand 150 psi or more. I am not certain, but I think about 14 psi is around atmospheric pressure (101.325 kPa). I thought:increased pressure = increased temperature decreased volume = increased pressure (and therefore, increased temperature)...

In theory, it should be about 2400 K, no? Yet, the bottle does not show any melting. I cannot even get a little piece of solder inside to melt. Is the heat loss during the thirty to sixty seconds of pumping that extreme? Or, is my understanding of the relationship between temperature and...

Does a material's magnetic permeability affect how much of said material a magnet can lift? For example, say a magnet can lift 1 unit of weight of a material with a permeability of 2. If another material has a permeability of 4, could the same magnet instead lift 2 units of weight of this...

Why I was wondering is, I was looking at Magcraft's selection of magnets. Taking into account the differences in thickness, http://www.rare-earth-magnets.com/p-5-nsn0592.aspx" of theirs are the strongest. So if you were to stack them, and their magnetic fields add-up linearly, then they are...

If I were to use a gaussmeter to measure the strength of a magnet's magnetic field, would the value read be double if I were to stack two (of the same kind of magnets) on top of one another?

I could not find anything online indicating that such was so, but... If electrolysis of a solution of zinc sulfate results in zinc and sulfuric acid, is it also correct that electrolyzing a solution of aluminum sulfate will result in aluminum and sulfuric acid?

Wet coffee filters. Then later, just whatever my multimeter's probes were made of.