MOSFET newbie question

[Zapatero]

I have an issue where I switch LED strips on and off using a mosfet. The gate voltage is (~6VAC). This switches a the LED strips with a 12VDC source. It works well with the single color LED strips. However, when I tried to switch a RGB controller (also 12V DC), I get different results.
The LEDs work, but they are very dim. It almost seems like the mosfet is not allowing enough current to pass through it to drive the controller. The mosfet is rated for more than enough current(max draw on the controller is 6A and the FET is rated for 10A. I am probably drawing less than 1A for the small # of leds I am using).
I also tried a bridge rectifier on the gate input and smoothed it out with a cap. This yielded the same result. This is the first time I have used a MOSFET so it's new territory to me. Any thoughts as to what the issue could be???

Thanks for any info.

 

[ronsimpson]

Many MOSFETs need more than 6V on the gate, to handle high current. What is the part number?

Do you really have 6vac on the gate? like 60hz from the power line?

 

[Zapatero]

Yes, it is 6VAC, 60Hz, It is the source voltage for general illumination lights in a pinball machine. I am using it to drive LED strip lights and trying to get them to switch on and off along the GI lighting).
The part# for the mosfet is: 13N10L

If there is a better way to switch a load using an AC source voltage, I am open to suggestion. A darlington pair transistor?

Thanks.

 

[ronsimpson]

The 13N10L turns on at low voltage very well. It is very much on by 4 volts Gate to Source.

Sending AC into the gate has a problem. The gate will be off for all the the negative half of the cycle. And it will be off for part of the positive half of the cycle.

I can't see the relationship between your 12V and the 6Vac. It might be that the 12V negative side is connected to one of the 6vac wires.

The bridge and capacitor should make a good 5 volts DC. You will loose some voltage there but it should work. Again I can't see the big picture.

Generally the LEDs are from +12V to the drain of the MOSFET.
The MOSFET-Source goes to -12V.
Turn on voltage is from MOSFET Gate to Source.

 

[diy didi]

Rectify the gate voltage to DC. Add a 1Meg resistor across Gate Source to ensure it switches off and discharges gate capacitance.