You followed the recipe exactly, and yet your cake is not baked evenly? This can happen because of the temperature sensor of your oven.
You must know that every oven has its characteristics. In this article, we will examine a cause that you may not necessarily know: the problem with the temperature sensor.
When baking your dishes, the recommended temperatures may need to be changed slightly depending on the oven.
Do you think the temperature setting of your oven does not work correctly anymore?
Maybe the heating resistors need to be replaced or the thermostat. It can also be a problem with the temperature sensor which we will discuss below.
A little history of temperature measuring instruments
Before 1597 there was no other way to measure the temperature than by direct contact!
This year, the ingenious Galileo Galilei invented a device called a thermoscope, which can able to measure the changes in the temperature.
Later, in the 17th century, the research and work on liquids (mercury, ether, alcohol) began, and the first calibrated thermometer based on this principle appeared in Florence in 1650.
The temperature sensors of the ovens have another system. These are thermocouples in which two different, welded together metals generate an electrical current when heated. It can also be a platinum sheet that is sometimes wrapped around a rod.
What is the purpose of the temperature sensor?
In your oven you notice a thin metal bar – often top left or right – that is directed into the interior of the oven. That is the temperature sensor in your oven.
Temperature sensor task is to measure the temperature inside the oven and transmit it to the thermostat (a small component behind the regulator knob).
Thanks to the sensor, thermostat knows when the right temperature has been reached and when it needs to stop heating the oven.
How to remove the temperature sensor?
To test your temperature sensor, you first need to remove it.
Note: For safety reasons, you should first disconnect the oven from the power supply!
Now gently pull the oven away from its location and check at its back. Remove the back panel or cover with the suitable screwdriver. Check the position of the sensor from inside the oven. This will give you the idea of where to look on the backside for removing temperature sensor. Usually, they are fastened using one or two screws.
Gently remove the screws and pull it out.
How to check the temperature sensor?
To test your temperature sensor, you will need a multimeter.
Set the device to “Ohm Ω.”
The majority of the sensors are PTC resistors (PTC = positive temperature coefficient), but models use NTC resistors (NTC = negative temperature coefficient)
What does that mean?
In the case of PTC probes, the ohmic resistance increases with temperature, while with NTC probes, it decreases as the temperature increases.
Connect two connectors (or each connector of the single connector) to one of the two terminals of the multimeter.
Now note down the results for the following values.
Use the following example to understand:
For PTC probes:
|Temperature (F/C)||Resistance (ohms)|
|20°C / 68°F||535 ohms|
|100°C / 212°F||645 ohms|
|200°C / 392°F||853 ohms|
|300°C / 572°F||1035 ohms|
For NTC probes:
|Temperature (F/C)||Resistance (ohms)|
|0°C / 32°F||32550 ohms|
|20°C / 68°F||12488 ohms|
|30°C / 86°F||8059 ohms|
|60°C / 140°F||2490 ohms|
These values may vary but should not be equal to 1.
If this is the case, your temperature sensor is defective.
You can test your sensor under different temperature conditions to see if the ohm value changes appropriately.
That’s it !
You have tested the electrical resistance of the temperature sensor of your oven yourself.
If you are not getting the expected readings, you can replace the sensor.
Are you interested in buying the toaster oven?
Don’t forget to check out our guide for buying toaster oven here.