Hi All,
The power switch I am using on my amp has an integrated LED, as per below:
https://www.mouser.com/ProductDetai...3Li2QhXa0qUQ=&countrycode=AU¤cycode=AUD
I was hoping to operate the LED from the heater supply. However, my heater supply centre tap was going to be elevated to +35V, using a voltage divider hooked directly to B+.
I feel like this probably is NOT a good idea. While it would probably be fine most of the time, if there was some kind of component failure we could potentially see the LED being fed the full B+ voltage. Not a good situation given it is going to be touched when the switch is operated!
Interested to know if this is a legitimate concern or if I am just being paranoid. Presumably the switch has some kind of internal isolation, though possibly not for the voltages concerned.
Many thanks,
Greg
The power switch I am using on my amp has an integrated LED, as per below:
https://www.mouser.com/ProductDetai...3Li2QhXa0qUQ=&countrycode=AU¤cycode=AUD
I was hoping to operate the LED from the heater supply. However, my heater supply centre tap was going to be elevated to +35V, using a voltage divider hooked directly to B+.
I feel like this probably is NOT a good idea. While it would probably be fine most of the time, if there was some kind of component failure we could potentially see the LED being fed the full B+ voltage. Not a good situation given it is going to be touched when the switch is operated!
Interested to know if this is a legitimate concern or if I am just being paranoid. Presumably the switch has some kind of internal isolation, though possibly not for the voltages concerned.
Many thanks,
Greg
That switch mechanism is available with versions where the LED is powered by 110 and 240 volts, so I would expect there is sufficient insulation between the LED and the outside world to be safe in your circumstances.
https://au.mouser.com/datasheet/2/140/E_Switch_10082019_SAV4-1660463.pdf
https://au.mouser.com/datasheet/2/140/E_Switch_10082019_SAV4-1660463.pdf
The LED would fail open if fed a high voltage, there is normally a thin wire to connect the positive and negative wires, less than 0.2 mm, look at a clear LED with a magnifying glass. So you should not worry too much.
You can feed the LED from another lower voltage part of the circuit...they last years if the supply is within limits, if properly mounted, with a heat sink if needed.
Street lights, home bulbs...all pretty reliable, and most do not go bang if the LED fails.
You can feed the LED from another lower voltage part of the circuit...they last years if the supply is within limits, if properly mounted, with a heat sink if needed.
Street lights, home bulbs...all pretty reliable, and most do not go bang if the LED fails.
I don't know about the LED's efficiency, but what about making it part of the elevation voltage divider, preferably part of the ground side resistor?
Basically, you can feed the LED from anything you want if there's sufficient isolation from the switch's AC part (which presumably is).
Best regards!
Basically, you can feed the LED from anything you want if there's sufficient isolation from the switch's AC part (which presumably is).
Best regards!
It is usual to connect the led through a diode and a dropper resistor and place it across the 6.3v AC heater supply. 1n400* and 1k will give about 7mA across the led. It won't matter where the level stands then, assuming you feel the need to elevate the heaters for some odd reason.