problem with the 2k VR in 20vac.........

problem with the 2k VR in 20vac.........

the VR is modified to control the 20V 50hz vibrator......

the VR easy to get burned after awhile...

i need an alternative rugulator circuit to replace the VR but the S-wave need to smooth like using normal high Watt VR....



comments are welcome......

thx.



adax811.

You haven't mentioned the current requirement.

It sounds like you've exceeded the power dissipation rating of the variable resistor.

You need a high powered variable resistor, also known as a reostat.

Another option would be to add a variac on the primary of the 20V transformer.

Hero999 said:

You haven't mentioned the current requirement.

It sounds like you've exceeded the power dissipation rating of the variable resistor.

You need a high powered variable resistor, also known as a reostat.

Another option would be to add a variac on the primary of the 20V transformer.

Click to expand...

the ampere for the vibrator is 0.7A (i applied clamp meter to it) when i supply full 20VAC to the vibrator........
in addition, can u provide me where to get the parts, which i'm living in asia......

a switcher. since you already have a since wave you do not want to regulate it, just down convert it.

I do not normally recommend 555s and the like as switchers because they can not regulate, but you do not want it to regulate. A simple 555 PWM, a FET, an inductor, and a capacitor.

Dan