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    finding 4 pin connectors for own wires

    Hi Everyone, I am searching for 4 pin connectors both male and female to which I can add my own wires. There are jst connectors available but they already come with attached wires. Is there any such connector available. Power supply rating 12v 5 amp. thanks
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    Help me in calculating base resistance for transistor

    Hi, I am making a circuit for a led chaser. the leds should glow one by one. I am testing the circuit with one led for each transistor later I will add array of leds to each transistor. I want the base resistor value to make the transistor turn on. Leds will have resistors to limit current...
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    Confusion about led's forward voltage

    Hi, I have confusion about the forward voltage of leds. Do the colored diffused dome type of leds have same forward voltage as the clear dome type? e.g. Blue colored diffused dome type led will have same voltage as the clear dome type? colored diffused dome type Clear dome type thanks
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    Strange voltage variation in circuit

    Hi, I made a circuit which turns on according to sounds. actually it toggles. One loud sound, it turns on and in the next, it turns off. When I measure voltage across the electret. it is around 6 v. I am using 9 volt battery for power which is producing around 8.5 volts. Now the problem is...
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    Does the TDA2030 need negative potential?

    Hi Everyone, Do TDA2030 needs negative voltage also? I mean if I use a rectifier for 12 v, I have to pass +12v and -12v to TDA2030 for proper audio amplification? thanks
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    do parallel connected leds consume more power?

    Hi, I wanted to know if leds which are connected in parallel to power source consumes more power than leds connected in series? I read somewhere that leds in series consume less power. thanks
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    Change in resistance of electret microphone with sound

    Hi, I read electret microphone changes its resistance according to sound applied. the resistance is proportional to loudness of sound. can anyone provide me some information about it? I want to calculate resistance for different sounds? I don't have oscilloscope. is there any information on...
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    Electret microphone is giving unsual resistance

    Hi, I am trying to make a clap switch, schematic is given below: I am using 9v battery but it is giving 7.55v currently. When I am measuring the voltage in microphone voltage divider part. it is coming 6.7v. which is strange because If i calculate the resistance for the voltage then the...
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    TDA2030 amplification is very less

    Hi, I am trying to amplify the sound generated by timer 555 circuit with TDA2030A. But, the amplification is very less, hardly audible. Please check the circuit below: TDA2030A amplification circuit is taken from datasheet. I didn't placed the capacitor (please check the capacitor outlined...
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    UM66 is not giving full tone

    Hi, I made a UM66(BT66) door bell circuit. it is operated from mains by main door bell switch. It has a LM386 amplifier circuit also. My problem is BT66 is not giving full tone on pressing the switch. I mean whenever the switch is pressed and released, the bell circuit should ring until the...
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    Can I use resistor instead of pot with LM386?

    Hi, I am using a LM386 amplifier to amplify um66 output. Speaker is 8 ohm 1 watt. Supply voltage in 9v I don't want to vary the sound level so, the pot is not needed here. Just I want maximum of sound. So, my question is , can I use 10k resistor instead of a 10k pot in the circuit given...
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    Audio level with potentiometer

    Hi, sorry for my foolish question, I am a newbie. I want to know at what resistance we get maximum audio level? I mean If we use 10K potentiometer in a amplifier circuit, will we get maximum audio level at 0 resistance or 10K resistance. thanks in advance.
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    amplifier circuit(2N3904) giving no sound

    Hi Everyone, I am a beginner hobbyist. I made a ding dong bell circuit, you can see it below but, sound at output was too low. I am using a 8 ohm speaker, may be 3 or 5 watt. so, I added a dual 2N3904 circuit for amplification of sound, you can see the circuit below: but there is...
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