In the simplest terms, an ohmic device is a material that always provides a uniform resistance to the flow of electricity. A non-ohmic device, on the other hand, does not offer a uniform resistance. In this blog post, we will explore what makes these devices different and discuss some of the most common applications for each type.
What are Ohmic and Non-Ohmic Devices?
There are two types of electrical devices: ohmic and non-ohmic. Ohmic devices are devices in which the resistor is in perfect contact with the current-carrying wires, so all of the electricity flows through the resistor. In a non-ohmic device, some of the electricity bypasses the resistor, so not all of the electricity flows through it.
Advantages Of Ohmic Devices
1. Efficient energy usage
Ohmic devices can be used in power converters that enable efficient energy-saving because more of the input voltage can be converted into electrical output power without getting wasted as heat, which would occur with an ordinary resistor [or so]. [Not sure if this should go here]
2. Infinitely adjustable Ohmic value
Since Ohmic devices provide resistance, their value depends on how much of the energy is dissipated [or absorbed] as heat. This means that Ohmic devices can be infinitely adjustable and will provide different values with different levels of power dissipation in order to meet the demand in a circuit with an electric current.
3. Versatile
Ohmic devices can be used for multiple purposes, such as measuring temperature and providing resistance in different circuits with electric currents.
4. Low cost
Since Ohmicity only provides resistors, it enables them to be low-cost compared to other components that vary more significantly In price. In addition, there are no additional costs of adding extra features into the device, which makes it more economical than its counterparts.
5. Easy to work with
The Ohmicity devices can be easily shaped and molded, making them easy to work with when it comes to using them.
Disadvantages Of Ohmic Devices
1. The use of non-renewable resources to produce electricity
The majority of power stations burn fossil fuels such as coal or gas to generate heat which is then used to change water into steam. The steam produced by this process turns huge turbines which drive generators, producing electricity from magnets moving around wire coils. In most cases, more energy is used up in the process than is obtained from the fuel sources.
2. Nuclear power station accidents are extremely expensive
There have been many oil spills at sea, however, it is estimated that the Exxon Valdez accident which occurred in 1989 and resulted in an oil spill of approximately 10.8 million gallons will cost approximately $3.5 billion to clean up. By comparison, the Chernobyl accident on the 26 th April 1986 was more than 3,000 times worse and by November 2000 it had cost nearly $130 billion to try and avert long-term consequences. At Fukushima (2011) no expense has yet been spared as the nuclear engineers struggle to stop 4 out of 6 reactors from becoming superheated steam canisters each with 1,535 fuel rods inside, each rod containing radioactive uranium pellets.
3. Nuclear power is not a suitable option for many countries, especially small ones
Even though the use of nuclear power can be very expensive for a country, there are some large nations that have been able to afford it. In particular, France has been extremely successful at generating income from its 59 reactors and has been exporting electricity to other countries such as Italy and Germany. This however is an exception rather than the rule as only 8% of the world’s uranium comes from mines in developed nations whereas 40% comes from developing nations. For example, Canada exports 88% of the uranium mined within its borders.
4. The waste produced by nuclear power stations remains radioactive for far too long
There have been no fatalities resulting from radiation emitted from nuclear power stations. However, there have been fatal accidents associated with the handling of the waste from those power stations. In one case a tank containing radioactive material exploded killing 50 people including 29 firefighters. The most notorious incident was at Chernobyl, Ukraine on 26 th April 1986 where at least 28 direct deaths and several thousand cancer fatalities were recorded as a result of core meltdown and explosion.
It must be noted that even though it is possible to dispose of unspent fuel rods which are no longer dangerously radioactive, this process is not cheap and by its very nature leaves highly dangerous materials which can be used by unscrupulous countries for the manufacture of nuclear weapons.
5. Venting and pollution of fossil fuels during operation
The use of coal or natural gas is extremely dirty and the pollution created during their use by power stations not only contributes to global warming but also leads to serious health problems for many people. For example, in the USA alone it has been estimated that more than 1.7 million people a year lose between 7-30 days of work on account of conditions such as asthma, bronchitis, and emphysema while complying with Federal standards costs industry more than $60 billion a year. In China, there are plans to build new coal-fired plants at a rate of two each week which will add greatly to this problem.
Advantages Of Non-Ohmic Devices
Advantage 1 – Heating Effect Reduced
In an incandescent bulb filament when direct current flows through it, it warms up due to Joule heating. If alternating current also contains alternating voltage then the amount of power used is reduced by 50%.
Advantage 2 – Energy Savings
When appliances use an energy saver switch they use half the energy as compared to using a regular switch since there is no continuous flow of power through them. In some countries this type of switch is compulsory.
Advantage 3 – Lowered Power Bills
The amount of power used by appliances can be lowered using an energy saver switch if the voltage remains the same then it will result in reduced consumption. A general reduction in power bills of at least 10% can be expected when appliances are regularly switched off when not in use.
Advantage 4 – Lower Carbon Footprints
As compared to non-ohmic devices with fixed resistance semiconductor devices that have variable resistance depending on the level of current drawn offer more efficiency and generate less heat. This helps to reduce carbon footprints as there is less waste heat released into the environment. Reduction in carbon footprint depends upon the quantity of waste released by household appliances like washing machines, refrigerators, air conditioners, etc.
Advantage 5 – Reduced Electric Bills
Availability of energy-efficient appliances saves money and reduces the amount of power used by appliances such as microwave ovens, dishwashers, and washing machines. The lower the power consumption, the easier it is to control electric bills. Also, demand can be controlled so that expensive equipment like stabilizers and inverters do not need to be maintained regularly.
Disadvantages Of Non-Ohmic Devices
1. They can fail suddenly without warning. Because they do not obey Ohm’s law, overloading them may damage them permanently such that they cannot work again.
2. They have a very low tolerance. Their resistance changes by a large amount compared to ohmic devices. Often, non-ohms will only work within a certain voltage range and become unreliable if this range is exceeded.
3. They usually require additional components for proper operation. When overloaded, they may shut down or produce too much power that other components cannot handle. In order to prevent these effects, capacitors or inductors are often used with them.
4. They can be expensive as special equipment is required to test their characteristics. Additionally, switches and other electronic parts must be constructed so the device will not be accidentally turned on when it should be off or turned off when it should be on. This is more work from those assembling the product, which is reflected in the final price.
5. They may not be able to handle changes in temperature. If they are used in an environment that experiences large fluctuations in temperature, their properties may change enough that they will fail to work at all. Therefore, care should be taken when using them outside of stable environments.
What Are Some Applications For Each Type Of Device?
1. Non-ohmic devices can be used to replace resistors in certain circuit problems.
2. Ohmic and non-ohmic device’s equations can be used to find the voltage across a resistor or capacitor is given current or resistance values respectively.
3. Ohmic and non-ohmic device equations can be used to find the current flowing through a resistor or capacitor given voltage or resistance values respectively.
4. Both ohmic and non-ohmic devices’ current gain (beta), input resistance (r_in), and output resistance (r_out) can be found using transistor datasheets.
5. Ohmic devices are used in transistors, which control the flow of current through an electronic circuit. Transistors are typically used to amplify signals or switch currents on or off in a circuit.
