How to amplify signal to transistor.

I have created a circuit using the diagram found here:
The only differences in my circuit are that I only have used one LED and one 3 volt coin battery. I want to install this circuit in my headphones with the L/R and Ground soldered to the terminals of the speakers. On testing the circuit, I found that the light is only clearly illuminated when the volume is set to max, otherwise, it is very faint. I want it to work at lower volumes. How do I amplify the signal going to this circuit without building a headphone amp? I only want to amplify the signal going to this circuit, not the headphones. Thanks in advance.

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Sbmsjr3 years ago
plz help me I'm trying to make drum with piezo (https://www.instructables.com/id/WORLDS-CHEAPEST-VIRTUAL-DRUM-at-10-Rs500-us/) but I have no ic to amplify signal the coming from piezo .................
we can amplify signal without any ic .......plz help me
iceng Sbmsjr3 years ago
Yes !

You really need to ask your own question
Sbmsjr iceng3 years ago
I want to amplify piezo signal without any ic
iceng Sbmsjr3 years ago
I did understand that

TRY to understand me !
A circuit using a transistor or two per amplifier with its attendant resistors and capacitors
is far more complex then one IC that has four individual amplifier / comparator units
in a single14 pin IC (Integrated Circuit).
comp ckt.gifthree-transistor-audio-amplifier-circuit.jpg
Building a headphone amp is the best way to amplify the signal for the circuit.
or buff up the transistor with a second transistor; darlington pair style :D
Vijster1 (author)  frollard4 years ago
That sounds interesting. How would I do this or incorporate this with the diagram that I am using (below)? Could you give me the specifics/a schematic?
http://en.wikipedia.org/w/index.php?title=File:NPN_common_emitter_AC.svg is an amplifier circuit you could use before the TIP31

has the explanation of all the values. basically, the circuit I added is an amplifier -- it takes the input signal and multiplies its intensity. The higher intensity is seen by your TIP31 transistor as a bigger amplitude, and makes the leds on more/brighter. Keep in mind, your circuit drawing has no protection resistor for the leds, and they'll likely burn out quickly like that.
transistor amplifier.PNG
iceng4 years ago
Here you go.

A rough darliington transistor configuration.
I am almost sure 3V is too low for this circuit that is why two cells
and two LEDs in series.
If you don't want two LEDs put a 250 ohm resistor in place of one.

This darlington ckt can go into thermal run-away and that 47 ohm
resistor wont let it do that.

Vijster1 (author)  iceng4 years ago
I am likely to test this in the morning and tell you of the results.
Vijster1 (author)  iceng4 years ago
Thanks! One last question - what is the part to the left of "ICeng"? Is it the same schematic in another a non-pictorial form? I appreciate all of your help.
Vijster1 (author)  Vijster14 years ago
It seems I am right - I spoke too soon. On further observation I identified the symbols for LEDs, resistors, and transistors. Thanks again!