I've been reading and doing experiments from the Make: Electronics book and had a few questions. I'll number my questions in red, the ones with a letter are the ones for which I am looking for an answer:
1) If we had 6V supply and a 100 ohm resistor in series with a collector of the transistor that amplifies at a 24:1 ratio such as the 2N2222 and the emitter to ground (see attached diagram) and no other device is connected in series, even though the transistor amplifies current, the maximum current would be limited by the resistor like so: 6/100 = 0.06 A by ohms law and the transistor cannot amplify to any more current than 0.06 A in this case.
1a) Is this correct?
1b) It's a little confusing to a beginner like myself to think about amplification because first I thought to myself "Does the transistor make current? Is that how it amplifies it and where do the limits come from?"
2) One of the experiments uses a 2N6027 PUT and a 2N2222 with a 0.0047uF capacitor and a couple of resistors (see attached diagram). The speaker barely makes any sounds when the 2N2222 transistor is eliminated.
So in the diagram, lets remove the 1K resistor and the 2N2222 transistor (Q3). Now wire 100 ohms to the bottom of the 2N6027 where the 1K was removed from, and the speaker in series with that and to ground.
To me it feels like this should work because the PUT isn't supposed to have much resistance inside it once it lets current through (what I learned), and the speaker is basically now wired to the capacitor, which acts as if it's the power source and the speaker isn't going to get much current from the main power source due to the large 470K resistor.
2a) The capacitor is theoretically supposed to be able to deliver infinite current if it was shorted, correct?
2b) Now, it appears that just above 2.7V is around what the capacitor is charged to before being discharged, is this correct? Or is it 3.3V?
2c) My other question: Is the capacitor not able to deliver enough current or is it that it does not store enough voltage for the speaker to make enough sound (it's very very quiet)? Basically, why do we need to add a 2N2222 transistor to make the speaker easily audible? Is it possible to make the speaker louder using just the Programmable Unijunction Transistor?
Does the PUT transistor have a maximum current that it can handle and thus is limited to delivering a limited amount of current? Is this why the speaker is very quiet?
Thank you for all the help!
1) If we had 6V supply and a 100 ohm resistor in series with a collector of the transistor that amplifies at a 24:1 ratio such as the 2N2222 and the emitter to ground (see attached diagram) and no other device is connected in series, even though the transistor amplifies current, the maximum current would be limited by the resistor like so: 6/100 = 0.06 A by ohms law and the transistor cannot amplify to any more current than 0.06 A in this case.
1a) Is this correct?
1b) It's a little confusing to a beginner like myself to think about amplification because first I thought to myself "Does the transistor make current? Is that how it amplifies it and where do the limits come from?"
2) One of the experiments uses a 2N6027 PUT and a 2N2222 with a 0.0047uF capacitor and a couple of resistors (see attached diagram). The speaker barely makes any sounds when the 2N2222 transistor is eliminated.
So in the diagram, lets remove the 1K resistor and the 2N2222 transistor (Q3). Now wire 100 ohms to the bottom of the 2N6027 where the 1K was removed from, and the speaker in series with that and to ground.
To me it feels like this should work because the PUT isn't supposed to have much resistance inside it once it lets current through (what I learned), and the speaker is basically now wired to the capacitor, which acts as if it's the power source and the speaker isn't going to get much current from the main power source due to the large 470K resistor.
2a) The capacitor is theoretically supposed to be able to deliver infinite current if it was shorted, correct?
2b) Now, it appears that just above 2.7V is around what the capacitor is charged to before being discharged, is this correct? Or is it 3.3V?
2c) My other question: Is the capacitor not able to deliver enough current or is it that it does not store enough voltage for the speaker to make enough sound (it's very very quiet)? Basically, why do we need to add a 2N2222 transistor to make the speaker easily audible? Is it possible to make the speaker louder using just the Programmable Unijunction Transistor?
Does the PUT transistor have a maximum current that it can handle and thus is limited to delivering a limited amount of current? Is this why the speaker is very quiet?
Thank you for all the help!
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