People often wonder about the distinctions between electric cooking stoves, ranges, cooktops, and stovetops. Which ones tend to be combined? Which ones are most efficient? They can all cook your favorite classic dishes, but each system operates in a slightly different way, using different heating mechanisms.
What Is a Cooking Range?
A standard range is a large stand-alone appliance made to fit between two base cabinets or a wall on one side and a base cabinet on the other. Four or five elements sit on the stovetop at counter level, with the console and its controls on the back guard or in front of the range.
Some range models incorporate a downdraft fan along the rear or across the width in the center of the stovetop surface. The bottom of the appliance usually contains an oven box for baking or roasting.
Not all kitchen stoves and ovens come as one unit. One popular concept is the counter cooktop unit, which doesn't necessarily need an oven.
With the oven box as a wall-oven insert installed at a different location in the kitchen area, within a cabinet or wall at about 30-inches from the floor for easier accessibility.
Conventional Coils vs Radiant Heat
Any electric stovetop uses conventional coils or radiant heat to produce the heat for cooking, or otherwise heats up a specially constructed cookware by induction, involving the use of magnetism instead of heat.
Induction technology is a whole different ballgame, relying more on magnetism than electricity.
The conventional stovetop comes with several coiled elements, each one plugged into a recessed enclosure within the cooktop surface, slightly elevated from the surface of the stove.
With coil elements, the heat transfers directly to your cookware, and in terms of performance, a lot of the heat is also dissipated in the surroundings, which reduces efficiency.
Conventional coils, however, are much easier to access when it comes to repairing or replacing the element, and the appliance is also cheaper to purchase than its ceramic and glass counterparts.
Ceramic and glass stovetops give you a very modern and clean appearance with their smooth surface making it easier to clean, having their four or five elements hidden underneath the surface. The location and shape of the elements are usually indicated with demarcation circular lines on the glass.
The glass top boxed-in enclosure is what makes this cooktop more efficient by transferring the heat from the coils directly to your cookware—by the heat emanating to the glass surface which then transfers it to your cookware by induction.
Although the smooth surface is easier to clean, great care must be taken choosing the proper products and tools used on the surface as abrasive products and sharp tools can scratch the polished surface.
Safety Note: As a precaution, radiant coils are complemented with a built-in “limiter” to protect against overheating by shutting down the power to the coil elements when they get too hot. You can easily see the probe containing limiter running from the outside perimeter of each coil towards its center while it's red hot.
As far as the oven elements go, what is a discrepancy in cooktop coils becomes an advantage as what is required in the oven box is heat dissipated throughout its entire cubic space, the overall result depending on how evenly throughout the heat is distributed.
With the selector switch set on "Bake," the bottom element controlled by the thermostat will come on to warm up the oven. The top element might also come on in conjunction with the bottom element, but in short bursts only, just to even up the heat throughout the oven cavity and cook more evenly.
The Broil selection on the switch will activate the top broil element only. Some ovens might have a dual top element and possibly two settings for the broil selection, one setting for the outer element only, the other for both elements.
Finally, you have the convection ovens with a fan inside the back wall that constantly moves the hot air around and maintains a constant even temperature throughout every cubic unit of the oven box.
The oven elements are made the same way as the coils except that instead of being formed into a spiral, they are shaped to fit specific oven sizes and shapes.
Controlling the Heat
In both of these technologies, the same circuitry is used to control the heat. In order to work, your range uses a series of heating elements which are controlled using two of at least three different systems, some mechanical, some electronic, and others a combination of each.
Figure 2 shows a PC control board inside a wall-mounted oven. Each system has its specialty as to what exactly is to be controlled and how, as you sometimes need to control the temperature and in other applications the frequency of On/Off cycles to produce the right amount of heat.
Each heating element on your stove and oven is connected to its own temperature control switch, which when dialed or set to a specific heat closes the circuit sending the electric current through the element, until it reaches a specific temperature (of the oven) or a specific time delay (for the coil elements) when the contacts open, stopping the current flow.
Once it cools back down to below the level of the control’s setting, the circuit is reactivated, restarting a new cycle.
The elements are also varied in types and in ratings throughout the cooktop and the oven. A small burner will draw approximately 1,200 watts of power while medium-size burners can draw 1,500 to 1,800 watts, and large burners rate at 2,500 watts or more. You want to be able to control that energy to different temperature levels.
On conventional stoves, heat is managed through a simmerstat control, which can be dialed from the "Off" position up to the "High" setting.
The simmerstat is the infinite control switch that operates from a bimetallic strip and controls when the contacts close and open. A bimetallic strip is made of two strips of different metals that expand at different rates when submitted to heat.
The two strips are attached together face-to-face with the wiring terminal at one end and a contactor at the far end. When the dial is rotated to the off position, the contactors open the circuit.
Then while rotated clockwise, a cam on the dial’s shaft rotates into action pushing against the bi-metal strip to close the contactors and send the current through. More rotation from the dial increases the amount of pressure applied.
The current flowing through the metal strips heats up the metal bands causing the inside band to expand but at a greater rate than the outside metal resulting in a decreasing pressure against the contactors until it opens the circuit.
With the current flow stopped, the strip cools down returning to its normal size and establishing contact again, starting a new cycle. That means that for the time that the elements are “On”, they operate at full power, but only stay on for as long as the pressure from the cam setting will permit. The average cooking temperature is therefore based on how long the cycle lasts.
Since the oven requires a more stable temperature control than the cooktop elements, it's more accurately controlled with a thermostat that can “sense” the temperature inside the oven box from a temperature sensor which is a thermistor (a heat-sensitive semi-conductor) that changes its resistance value with variations in ambient temperature.
It is encased within a metal probe which is inserted inside the oven chamber through the wall (Figure 3), and connected to the thermostat control in the console.
The control then reacts to whatever resistance reading it gets from the thermistor opening and closing electrical relays (little black boxes in Figure 4) that sends the power to each of the oven elements, turning them on and off at predetermined temperature settings.
Troubleshooting problems in electrical appliances requires knowledge of electronics, sometimes at a fairly advanced level. If you're thinking about giving it a try, check out some of our guides to fixing electrical heaters, cookers, and other appliances.