View attachment 66123
I modified my ham earpiece by adding this preamp for the microphone(earpiece). It worked at the beginning for a few times but after that it did not work. I got some noise when I pressed the mic button of the earpiece without my voice.
I use 9V battery. I doubt that the voltage supply for the base is sufficient or over the limit of the 2N3904 but I'm not sure. I tried two of the 2N3904 and got the same result. I tried using 100k trimmer for base but it nothing is better. I do not want to waste, if it's burnt, them any more.
Please advise me how to make this circuit work.
Thanks.
I modified my ham earpiece by adding this preamp for the microphone(earpiece). It worked at the beginning for a few times but after that it did not work. I got some noise when I pressed the mic button of the earpiece without my voice.
I use 9V battery. I doubt that the voltage supply for the base is sufficient or over the limit of the 2N3904 but I'm not sure. I tried two of the 2N3904 and got the same result. I tried using 100k trimmer for base but it nothing is better. I do not want to waste, if it's burnt, them any more.
Please advise me how to make this circuit work.
Thanks.