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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
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$begingroup$
I have a simple PAM8403 that I use to amplify sound,
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
asked Apr 7 at 13:46
Jonas Tuemand MøllerJonas Tuemand Møller
1133
$endgroup$
add a comment |
$begingroup$
I have a simple PAM8403 that I use to amplify sound,
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
asked Apr 7 at 13:46
Jonas Tuemand MøllerJonas Tuemand Møller
1133
$endgroup$
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
Apr 7 at 14:26
add a comment |
$begingroup$
I have a simple PAM8403 that I use to amplify sound,
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
asked Apr 7 at 13:46
Jonas Tuemand MøllerJonas Tuemand Møller
1133
$endgroup$
I have a simple PAM8403 that I use to amplify sound,
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
operational-amplifier led
asked Apr 7 at 13:46
Jonas Tuemand MøllerJonas Tuemand Møller
1133
asked Apr 7 at 13:46
Jonas Tuemand MøllerJonas Tuemand Møller
1133
asked Apr 7 at 13:46
Jonas Tuemand MøllerJonas Tuemand Møller
1133
asked Apr 7 at 13:46
Jonas Tuemand MøllerJonas Tuemand Møller
1133
asked Apr 7 at 13:46
Jonas Tuemand MøllerJonas Tuemand Møller
1133
1133
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
Apr 7 at 14:26
add a comment |
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
Apr 7 at 14:26
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
Apr 7 at 14:26
$begingroup$
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
Apr 7 at 14:26
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
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.
answered Apr 7 at 14:21
jusacajusaca
1,032420
$endgroup$
add a comment |
$begingroup$
If you look at the back of your amplifier board you will see you can pick up the power on the switch.
The Black arrow points to the switched +5V
You would connect your LED as follows:
simulate this circuit – Schematic created using CircuitLab
answered Apr 7 at 16:04
Jack CreaseyJack Creasey
15.5k2823
$endgroup$
add a comment |
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2 Answers
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active
oldest
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2 Answers
2
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$begingroup$
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.
answered Apr 7 at 14:21
jusacajusaca
1,032420
$endgroup$
add a comment |
$begingroup$
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.
answered Apr 7 at 14:21
jusacajusaca
1,032420
$endgroup$
add a comment |
$begingroup$
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.
answered Apr 7 at 14:21
jusacajusaca
1,032420
$endgroup$
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.
answered Apr 7 at 14:21
jusacajusaca
1,032420
edited Apr 7 at 14:28
answered Apr 7 at 14:21
jusacajusaca
1,032420
answered Apr 7 at 14:21
jusacajusaca
1,032420
answered Apr 7 at 14:21
jusacajusaca
1,032420
1,032420
add a comment |
add a comment |
$begingroup$
If you look at the back of your amplifier board you will see you can pick up the power on the switch.
The Black arrow points to the switched +5V
You would connect your LED as follows:
simulate this circuit – Schematic created using CircuitLab
answered Apr 7 at 16:04
Jack CreaseyJack Creasey
15.5k2823
$endgroup$
add a comment |
$begingroup$
If you look at the back of your amplifier board you will see you can pick up the power on the switch.
The Black arrow points to the switched +5V
You would connect your LED as follows:
simulate this circuit – Schematic created using CircuitLab
answered Apr 7 at 16:04
Jack CreaseyJack Creasey
15.5k2823
$endgroup$
add a comment |
$begingroup$
If you look at the back of your amplifier board you will see you can pick up the power on the switch.
The Black arrow points to the switched +5V
You would connect your LED as follows:
simulate this circuit – Schematic created using CircuitLab
answered Apr 7 at 16:04
Jack CreaseyJack Creasey
15.5k2823
$endgroup$
If you look at the back of your amplifier board you will see you can pick up the power on the switch.
The Black arrow points to the switched +5V
You would connect your LED as follows:
simulate this circuit – Schematic created using CircuitLab
answered Apr 7 at 16:04
Jack CreaseyJack Creasey
15.5k2823
answered Apr 7 at 16:04
Jack CreaseyJack Creasey
15.5k2823
answered Apr 7 at 16:04
Jack CreaseyJack Creasey
15.5k2823
answered Apr 7 at 16:04
Jack CreaseyJack Creasey
15.5k2823
15.5k2823
add a comment |
add a comment |
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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
Apr 7 at 14:26