say again? How much level? and where did you measure this?
What power source was used? impedance?
more sensitive?
The problem is the 10uF cap is 100x bigger than the 100nF cap and it tales a long duration to get enough pulses to charge it up to a few volts.. Changes LED driver to a Darlington configuration and use an active peak detector. or similar.
It does not have an emitter follower. Instead it has a PNP common emitter class-C amplifier that needs a signal level of about 0.5V to 0.6V peak to turn it on.In this design I Used emitter follower to act as current buffer and rectifier.
It does not have an emitter follower. Instead it has a PNP common emitter class-C amplifier that needs a signal level of about 0.5V to 0.6V peak to turn it on.
The electret mic has an output level of only about 10mV so the transistor will NEVER turn on unless there is a nuclear bomb blast nearby.
corrected belowAudioguru has not made any friends yet.
my dog died, corrected below
An Op Amp circuit can do much better than this, but FWIW ( for what it's worth.... )
Base Resistor ratio is sensitive to ON/OFF.
Since you did not use the 10uf capacitor then the LED blinks for every half-cycle of the audio so with continuous sound it is turned on for only half the time and appears dimmed.
The LED blinks with every half cycle of audio but the blinking for most frequencies is much faster than your vision can see it so again most sounds produced dimmed light.
You removed the 10uF capacitor then you also do not need the diode in series with the signal that reduced sensitivity.
The circuit had the base-emitter diode of the transistor charging the coupling capacitor but nothing discharging it so again the sensistivity was reduced.
I put the diode in series with the 10k resistor to ground so that its polarity is the opposite to the polarity of the base-emitter diode and it discharges the coupling capacitor on every half cycle for good sensitivity.
I increased the value of the 100nf capacitors to 330nF so that they pass low audio frequencies and added a 10uF important supply bypass capacitor.
Thank you very much sir. I'll make this one and will post the result.
BTW,
**Is that resistor 10 M or 10 K from the input (Mic input) ?
Ignore Ant/10M , I used 10K instead of 4.7K
** Can I use BC 547 (PNP) and BC557 (NPN) for the transistors?
YES
** Is there any option to adjust sensitive?
If you can attach clear image really appreciate.
Thank you very much sir. Tomorrow I'll make this one too and reply. Appreciate.
Replace 1M/6.5M with 1M trimPOT & ~6M fixed but limit range with a fixed R to adjust Vbe bias and load.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?