Ohms law and basic electrical terms

  Just a few of the term used in this blog and short description of what is meant by it.

Ohms law is the relationship between Voltage Volt, Current Amps and Resistance OHM.

Voltage, current and resistance.

Voltage is the power of the supply and can be 6v 12v or even 230v in a home. 

Current is the measurement of the amount of electricity a load is taking the larger the load the larger the current and also the larger the wiring needs to be , Amps and be AC alternating or DC direct current, Usually 230v AC in domestic homes.

Resistance is any restriction the electricity current has to face when travelling through the circuit and can be the wire and connection or terminal and the load itself will have a determined resistance than can be measured in Ohms.

Hertz , the way a generator works it will create AC alternating current this means it reverse direction of current, the amount of cycles per second between Positive and Negative is know as hertz in the UK its set a 50hz or 50 cycles per second.

Power  Is a measure of the electrical energy used by a component measured in watts. 100 watt light bulb, 1800w or 1.8Kw element. 

You need to know a little about these in order to understand how to fault find, its best to watch youtube videos and animations to understand this but its all relatively straight forward.

Use the triangle to calculate any of the needed value divide blow into top and Multiply the lower.

Here is an example - The resistance of a heater element is 20 ohms the measure voltage and UK domestic voltage is 230v to find current devide 230 / 20 = 11.5 Amps.

Top 3 dangers when using multimeter for 240v mains electrical work

Safety with electrics is obviously important , a multimeter can aid with safety but there are some dangers and its important to use the multimeter properly, in the correct setting with the correct test leads.

Here are three biggest safety issues when using a multimeter on electrical systems

1) Having meter in wrong function selection , this will give an eroneous measurement in the video below i test a live electricasl outlet in DC instead of AC and its shows a zero reading.

2) I then show another zero reading with the meter leads not correctly seated.

3) leaving the meter in amps , if you then try to , measure voltage, the voltage will appear on one end of the meter leads.

Please watch then video below for a demonstration of this.

Microwave door removal replacement ( how to take the door off )

Sometimes there are 2 removable hinges and other times just one you need to undo at the top and the bottom is a pull away hinge.

So this model i had to remove the outer cover with 5 screw and pull the cover away this then gives access to the upper door hinge. Undo the 2 retaining screws  and open the door it should then pull up and away from the microwave body.

There was a bottom hinge on this i undo the screws but it was not needed as it turned out 

Remove all 4 screws of cover and pull off the cover 

below is the upper hinge with 2 x screws

One the upper hinge is undone and door it pulled from catches it will pull away freely 

See the entire process in the video below 

Microwave Door Latch Spring Repair ~ when your door will close ~ open

To do this open the door , then pry off the outer plastic cover to gain access to the spring latch mechanism, the latch should pull up and move to one side to allow it to bew removed you then attach the spring and refit it can be very tight so take you time and do force it.

See video of this process below 

Microwave turntable plate not turning ~ motor replacement

Very easy fix you need to cut out the access panel first and then you gain access to the turntable motor ( make sure you isolate electric supply and work safe ). To replace motor pull of electrical terminals and undo retaining screw , motor comes away easy. The internal drive gear with need fitting onto the motor after replacing , when you replacethe motor access cover usually they will go in the opposite way round and secure with a screw to make safe.

Remove panel to access the motor

 one screw usually hold the motor in place 

easy to remove and replace

make sure you replace the plate drive gear after 

See a video of this entire process below

Microwave Top 5 common issues problems faults and easy fixes

 ** Warning avoid the capacitor inside these and do not open case with it plugged in**

First most common problem is the fuse test for continuity 

Then i would test the thermal cut outs 

Another issue could be the heater on the magnetron 

The doors usually have 3 micro switches 

and can be normally open or closed switches

so connect meter set to continuity and test by 

opening and closing the door

Test capcitor this one is 1 micro farad and it tested perfect

extra one test the primary and secondary windings of transformer.

See video of this below 

Microwave arcing crackling sparking ~ very easy fix

This piece of card is a mica wave guard very cheap to replace or try to clean it first with soapy water and let it dry before refitting and testing microwave again. The new piece will need cutting to size so keep you old one for a template.

It covers the below magnetron gap

Buy these guards here in Ebay UK

See video below of this full process