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How to add power-LED to my small amplifier?


How can I effectively reduce the voltage needed to activate a transistor?Is this 12 volt LED circuit correct?Using a 1.5V battery to increase the voltage from a headphone jack so it can switch a transistor at lower volumesHow would you increase voltage to drive an LED yet also keep it limited?Add a status LED to an existing deviceHow do I shine an LED when a PIR detects movement but keep it shining until a reset button is pressed?On/Off toggle with delay using bi-color ledSwitching two leds using transistor where one power feed still has small current present in off positionLED Driver Rsense valuesTransistors as Switch and Amp to control LED strip






.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;








2












$begingroup$


I have a simple PAM8403 that I use to amplify sound,



enter image description here



The volume switch also works as power-off, if I slide it all the way down it makes a click and its off.



My girlfriend is the user of this device and she often forgets to turn it off because its easy to overlook, therefore I want to add a LED that lights up when its on and off when its off.



How would I go about customizing it to achieve that?










share|improve this question







New contributor




Jonas Tuemand Møller is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$







  • 1




    $begingroup$
    So you need to detect when two pins of a variable resistor have near-zero voltage between them? And the existing voltage will be the audio signal. I'd impose a DC current (assuming the downstream amplifier can accept a (tiny) DC input, and then monitor the voltage for the presence and absence of any DC.
    $endgroup$
    – analogsystemsrf
    6 hours ago

















2












$begingroup$


I have a simple PAM8403 that I use to amplify sound,



enter image description here



The volume switch also works as power-off, if I slide it all the way down it makes a click and its off.



My girlfriend is the user of this device and she often forgets to turn it off because its easy to overlook, therefore I want to add a LED that lights up when its on and off when its off.



How would I go about customizing it to achieve that?










share|improve this question







New contributor




Jonas Tuemand Møller is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$







  • 1




    $begingroup$
    So you need to detect when two pins of a variable resistor have near-zero voltage between them? And the existing voltage will be the audio signal. I'd impose a DC current (assuming the downstream amplifier can accept a (tiny) DC input, and then monitor the voltage for the presence and absence of any DC.
    $endgroup$
    – analogsystemsrf
    6 hours ago













2












2








2





$begingroup$


I have a simple PAM8403 that I use to amplify sound,



enter image description here



The volume switch also works as power-off, if I slide it all the way down it makes a click and its off.



My girlfriend is the user of this device and she often forgets to turn it off because its easy to overlook, therefore I want to add a LED that lights up when its on and off when its off.



How would I go about customizing it to achieve that?










share|improve this question







New contributor




Jonas Tuemand Møller is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$




I have a simple PAM8403 that I use to amplify sound,



enter image description here



The volume switch also works as power-off, if I slide it all the way down it makes a click and its off.



My girlfriend is the user of this device and she often forgets to turn it off because its easy to overlook, therefore I want to add a LED that lights up when its on and off when its off.



How would I go about customizing it to achieve that?







operational-amplifier led






share|improve this question







New contributor




Jonas Tuemand Møller is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question







New contributor




Jonas Tuemand Møller is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|improve this question




share|improve this question






New contributor




Jonas Tuemand Møller is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









asked 7 hours ago









Jonas Tuemand MøllerJonas Tuemand Møller

1111




1111




New contributor




Jonas Tuemand Møller is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





Jonas Tuemand Møller is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






Jonas Tuemand Møller is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







  • 1




    $begingroup$
    So you need to detect when two pins of a variable resistor have near-zero voltage between them? And the existing voltage will be the audio signal. I'd impose a DC current (assuming the downstream amplifier can accept a (tiny) DC input, and then monitor the voltage for the presence and absence of any DC.
    $endgroup$
    – analogsystemsrf
    6 hours ago












  • 1




    $begingroup$
    So you need to detect when two pins of a variable resistor have near-zero voltage between them? And the existing voltage will be the audio signal. I'd impose a DC current (assuming the downstream amplifier can accept a (tiny) DC input, and then monitor the voltage for the presence and absence of any DC.
    $endgroup$
    – analogsystemsrf
    6 hours ago







1




1




$begingroup$
So you need to detect when two pins of a variable resistor have near-zero voltage between them? And the existing voltage will be the audio signal. I'd impose a DC current (assuming the downstream amplifier can accept a (tiny) DC input, and then monitor the voltage for the presence and absence of any DC.
$endgroup$
– analogsystemsrf
6 hours ago




$begingroup$
So you need to detect when two pins of a variable resistor have near-zero voltage between them? And the existing voltage will be the audio signal. I'd impose a DC current (assuming the downstream amplifier can accept a (tiny) DC input, and then monitor the voltage for the presence and absence of any DC.
$endgroup$
– analogsystemsrf
6 hours ago










2 Answers
2






active

oldest

votes


















6












$begingroup$

Measure the supply voltage pin of the PAM8403. The supply voltage should be switched on and off the switch. You can just solder an LED with a resistor in series from this pin to GND.
Depending on the color of your LED you have to choose the correct resistor.






share|improve this answer











$endgroup$




















    2












    $begingroup$

    If you look at the back of your amplifier board you will see you can pick up the power on the switch.



    enter image description here



    The Black arrow points to the switched +5V



    You would connect your LED as follows:





    schematic





    simulate this circuit – Schematic created using CircuitLab






    share|improve this answer









    $endgroup$













      Your Answer





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      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      6












      $begingroup$

      Measure the supply voltage pin of the PAM8403. The supply voltage should be switched on and off the switch. You can just solder an LED with a resistor in series from this pin to GND.
      Depending on the color of your LED you have to choose the correct resistor.






      share|improve this answer











      $endgroup$

















        6












        $begingroup$

        Measure the supply voltage pin of the PAM8403. The supply voltage should be switched on and off the switch. You can just solder an LED with a resistor in series from this pin to GND.
        Depending on the color of your LED you have to choose the correct resistor.






        share|improve this answer











        $endgroup$















          6












          6








          6





          $begingroup$

          Measure the supply voltage pin of the PAM8403. The supply voltage should be switched on and off the switch. You can just solder an LED with a resistor in series from this pin to GND.
          Depending on the color of your LED you have to choose the correct resistor.






          share|improve this answer











          $endgroup$



          Measure the supply voltage pin of the PAM8403. The supply voltage should be switched on and off the switch. You can just solder an LED with a resistor in series from this pin to GND.
          Depending on the color of your LED you have to choose the correct resistor.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited 6 hours ago

























          answered 6 hours ago









          jusacajusaca

          1,000320




          1,000320























              2












              $begingroup$

              If you look at the back of your amplifier board you will see you can pick up the power on the switch.



              enter image description here



              The Black arrow points to the switched +5V



              You would connect your LED as follows:





              schematic





              simulate this circuit – Schematic created using CircuitLab






              share|improve this answer









              $endgroup$

















                2












                $begingroup$

                If you look at the back of your amplifier board you will see you can pick up the power on the switch.



                enter image description here



                The Black arrow points to the switched +5V



                You would connect your LED as follows:





                schematic





                simulate this circuit – Schematic created using CircuitLab






                share|improve this answer









                $endgroup$















                  2












                  2








                  2





                  $begingroup$

                  If you look at the back of your amplifier board you will see you can pick up the power on the switch.



                  enter image description here



                  The Black arrow points to the switched +5V



                  You would connect your LED as follows:





                  schematic





                  simulate this circuit – Schematic created using CircuitLab






                  share|improve this answer









                  $endgroup$



                  If you look at the back of your amplifier board you will see you can pick up the power on the switch.



                  enter image description here



                  The Black arrow points to the switched +5V



                  You would connect your LED as follows:





                  schematic





                  simulate this circuit – Schematic created using CircuitLab







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered 4 hours ago









                  Jack CreaseyJack Creasey

                  15.1k2823




                  15.1k2823




















                      Jonas Tuemand Møller is a new contributor. Be nice, and check out our Code of Conduct.









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                      Jonas Tuemand Møller is a new contributor. Be nice, and check out our Code of Conduct.














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