Hello CBuk,

CBUK>>i would just like to add from a UK point of view that using resistors directly on the mains supply is a very dangerous thing to do because effectively your pic circuit will have potentially 'live' parts that have no isolation from the power line.
also dwane, you say the voltage will vary when an appliance is turned on, yes it will but only by mili volts, in the UK we have a tolerance of 4% for voltdrop in an electrical system, so if the voltage is dropping beyond this then there could quite possabily be a problem in the mains supply. another thing to consider is large current drawing appliances such as tumble dryers/ electric heaters/ fridges will cause surges and spikes on the mains when switching in and out.<<

yes, you are correct... Diodes can help in this area...


I was playing around with a Car Gas Pump with a friend of mine... we connected it to a PWM via a MosFet to control its speed. Found the MosFet getting very warm at low speeds, and very cool at high speeds. The motor was drawing about 1 amp. The MosFet was rated at 10A when sunk. Measuring voltage, we had spikes in the 50 Volt range and higher...

Put a diode across it, and the MosFet cooled down like it was supposed to...Solved the heat problem <g>.


CBUK>> if you do not have sufficient protection to snubb these surges and by using just resistor voltage deviders straight into the pics then they are just going to go pop!<<

Yip! you are correct....

I am just trying to figure out what the Gent wants to do, and how. I think MicoNavigateSystems has the right way how to think... What DOES he want. We can only assume, guess, and make broad assumptions, unless he gets more detailed.

I was only hoping to encourage him to try again. I am thinking that what he said was not what he meant. Sometimes in these computer forums, what comes across is not what we mean, because we cannot see the Body Language of the person talking.

Dwayne