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i need help with this diagram. Answered

Just the diagram...




Best Answer 8 years ago

Well it's a diagram. What help do you need or did you just want to show it to someone?

well, i can't find a 10uf capacitor and i was wondering if there was a way to make it more powerful.


8 years ago

I'm confused by this. It looks like a hypothetical circuit from a textbook. A practical circuit usually has more components. I think it unlikely anything this simple is going to be effective as a combined mic pre-amp and power amplifier. Sorry I can't be more help.

I've been following this with interest. Love the "Ruby" amp -- I may make one of those myself! Orthogonal to replies but intimately connected to the question, though; try out Eagle some time for generating a more readable schematic. There's a free version and it runs on all platforms.

I thought I recognized this circuit. It comes from BrunoIP's 'Ible. Yes it is a VERY low power amp. While a fun starting point, it is not something you would really want to keep for long. I know, i tried it.

If you need further clarification, I can show you my clean version of this design.


Here you go: Tiny Amp

At 125 mV input, you'l get about 80 mW of lo fi output. You'l also end up with DC bias on the speaker. Not good for longevity, both battery wise and speaker wise.

Re-design's suggestion is a very valid one. For a person who is starting out, the LM386 is a great low cost, almost bullet proof way to go.

If you want to learn more about discrete amplifiers, look at my thread on the Nuts and Volts forum that was started by the very same 'ible you chose. My final design ended up with just about 2 watts and virtually flat from 20-20kHz. Those guys over there are awesome.


my bad, this was a poorly written question, i should have asked.- "is there a way to make this amp more powerful n a low budget?"

yea but u would have to use a diff circuit so really no

COmpletely meaningless "drawing" it isn't a circuit - There's no way that the thing marked R1 is common to Q1 and Q2 Draw it as a proper circuit and repost it.

What kind of help do you need. I get the "just the diagram, but can you bit a bit less obtuse?" It's obviously a poorly drawn and quite old two stage transistor amplifier design (preamp and driver), and it has been noted that at least one other ible-clone has used the circuit. What beyond that don't you understand

I find it confusing in the way it's laid out, but I'd rearrange things more like this, but I still don't like it. Are you going off a circuit diagram from somewhere else?



diagram looks like it is "ROTATED" slightly wrong. Input should be on the LEFT. Speaker should be on the RIGHT. For simplicity of drawing, you could erase all battery MINUS connections and just show the 3 dashed lines indicating those wires are to ground (batt neg). I suspect R1 and R2 should be connected at the point their wires "cross-over" in the diagram. Other than that, you need to indicate exactly what question you have about the diagram. we are all confused about your question.

Yeah, looks like an amplifier -- speaker driven by q2 which is driven by q1. input going thru the 1m resistor into q2 perplexes me...allow very high signals to directly influence the driver?