The Coherer Effect As A Transistor

The goal of this scientific project is to use the Coherer Effect, which usually acts like a radio receiver as a transistor.
Eyasu Mulumar Tsion Mulumar
Grade 9

Hypothesis

If the Coherer Effect is used as a transistor to make the spark come from above/under/the side then, it would work best as a transistor if the spark is made to come from above as it will be able to successfully light up the LED and allow current to pass through the Coherer device during all four tests because the electromagnetic radiation would have no obstacles to travel through to reach the aluminum oxide on the aluminum balls within the Coherer device.

Research

The "Branly effect" which can be better known as the Coherer effect, had been discovered by a French physicist who was Edouard Branly back in 1890 on November 24th. Therefore, at the end of the nineteenth century, Edouard Branly discovered that the resistance of grains of a metal conductor would drop significantly as well as by a lot. Moreover, this would occur only if a spark had emitted electromagnetic radiation which made it to the granular metallic conductor. 

Before Edouard Branly discovered fthe Coherer effect, in June 1890 he had used the Wimshurt machine to study the effect of the created sparks and how different materials had reacted to the sparks. In his first experience he had flowed current through a resistant metallic disk to see the effect of the spark on it. The resistance of the electrically charged disk had significantly dropped by a lot. Then he had replaced the disk with a tube which had been filled with zinc particles that had oxide on them. Again, he found the same thing had happened as the resistance dropped while the conductivity rose. Soon after, he added barriers which eventually separated them by walls but, the effect had still worked.

The two important and significant components within the Coherer Effect that Edouard Branly had discovered include the oxide which is a compound made by containing one or more oxygen atoms along with another material such as aluminum. As well as the electromagnetic radiation which was used to create eddy currents in order to make the grains of the granular conductor mircowelds themselves togeether which breaks the oxide. In conclusion, to summarize the electromagnetic radiation emmited by a spark has the ability to break the oxide which is an insuultator that  can stop the current from flowing. Furthermore, that after the oxide is broken the current will beable flow freely through the Coherer device.

Overall, the Coherer effect is similar to a transistor. This is because, electricity will only flow through the Cohere device if a spark has been made. So, the spark acts like the base of a transistor in the sense that current will only flow thorugh the Coherer device if a spark has been made. In short, this proves that the Coherer effect can be used as a transistor because it is pretty similar to it and very closely the same.

Variables

The three variables included in the scientific experiment are the manipulated variable, the responding variable, as well as the controlled variables. The manipulated variable in this scientific experiment is the spark's location which is, whether it comes from the top, bottom, or side of the Coherer device. The responding variable in this scientific experiment is whether the LED successfully lights up during the tests, which means that the electricity successfully passes through the Coherer device. The controlled variables in this scientific experiment are the same amount of aluminum balls inside of the cup, the same type of aluminum foil, the same type of zap-it electrical racket, the same type of batteries, the same amount of voltage trying to flow through the LED, the same LED, the same wires, the same amount of resistance in the circuit, and the same battery holder.

Procedure

Materials:

  • 1 cup
  • 40 medium-sized aluminum balls
  • 1 zap-it electrical racket
  • 2 aluminum strips
  • 1 aluminum ball
  • 1 battery holder
  • 4 batteries
  • 1 LED

Procedure:

  1. Take the cup and put the 2 aluminum strips on opposite sides inside the cup with some parts of the aluminum sticking to keep the strips in place.
  2. Take the 40 medium-sized aluminum balls and place it inside of the cup. 
  3. Attach the LED to one of the wires, and then attach the other side of the LED to an aluminum strip on whichever side it is wanted on.
  4. Attach the other wire to the other aluminum strip.
  5. Attach both ends of the wires to each end of the battery holder, by putting the positive wire with the other positive wire of the battery holder and the negative wire with the other negative wire of the battery holder.
  6. Put the small aluminum ball into the zap-it electrical racket in between the two metal meshes, so that when the racket is turned on it will be able to make electrical sparks.
  7. Put two batteries correctly into the zap-it electrical racket and put the other two batteries correctly into the battery holder.
  8. Turn on the zap-it electrical racket then place it 7.5cm away from the Coherer device and observe how the LED turns on or doesn't whether the current successfully or unsuccessfully passes through the Coherer device.
  9. Repeat step 8, four times for each different design made by changing the position of the spark to come from either above, under, or beside the Coherer device.

 

Observations

Observations of Coherer Device as a Transistor
  Test #1 Test #2 Test #3 Test #4

Design #1:

Location of Spark Above Coherer Device

The LED turned on successfully because the current successfully passed through the Coherer device.

The LED turned on successfully because the current successfully passed through the Coherer device. The LED turned on successfully because the current successfully passed through the Coherer device. The LED turned on successfully because the current successfully passed through the Coherer device.

Design #2:

Location of Spark Beside Coherer Device

The LED flickered and didn't turn on successfully because the current wasn't able to successfully pass through the Coherer device. The LED turned on successfully because the current successfully passed through the Coherer device. The LED flickered and didn't turn on successfully because the current wasn't able to successfully pass through the Coherer device. The LED turned on successfully because the current successfully passed through the Coherer device.

Design #3:

Location of Spark Under Coherer Device

The LED didn't turn on successfully because the current wasn't able to successfully pass through the Coherer device. The LED flickered and didn't turn on successfully because the current wasn't able to successfully pass through the Coherer device The LED didn't turn on successfully because the current wasn't able to successfully pass through the Coherer device. The LED didn't turn on successfully because the current wasn't able to successfully pass through the Coherer device.

Control Group:

No Spark

The LED did not turn on at all, on its own because current didn't pass through the Coherer device.
The LED did not turn on at all, on its own because current didn't pass through the Coherer device.
The LED did not turn on at all, on its own because current didn't pass through the Coherer device.
The LED did not turn on at all, on its own because current didn't pass through the Coherer device.

Analysis

When analyzing this scientific experiment it can be seen that the results vary in each of the three different experiments. In the first set of experiments, the design was made by moving the location of the spark, above the Coherer device. It can be seen that with this first design, the LED on the Coherer device successfully turned on all of the time. This was because the spark from the Zap-it broke the aluminum oxide of the aluminum balls to allow current to pass through which completed the circuit, turning on the LED. Due to the spark coming from the top, the electromagnetic radiation emitted by the spark had no obstacles to pass through to reach the aluminum oxide.

In the second set of experiments,  the design was made by moving the location of the spark, beside the Coherer device. It can be seen that with this second design, the LED on the Coherer device didn't successfully turn on all of the time because for one or two tests it flickered a bit and shut off instead. This was because the spark from the Zap-it didn't always break the aluminum oxide of the aluminum balls so it didn't always allow current to pass through to complete the circuit to turn on the LED. Due to the spark coming from the side, the electromagnetic radiation emitted by the spark had an obstacle to overcome and pass to reach the aluminum oxide.

In the third set of experiments, the design was made by moving the location of the spark, underneath the Coherer device. It can be seen that with this third design, the LED on the Coherer device didn't successfully turn on at all and at most flickered and shut off. This was because the spark from the Zap-it didn't break the aluminum oxide of the aluminum balls to allow current to pass through to complete the circuit and turn on the LED, at all. Due to the spark coming from the bottom, the electromagnetic radiation emitted by the spark had an obstacle to pass through and overcome the distance from the bottom to the top of the Coherer device to reach the aluminum oxide.

The control group of this scientific experimental project was the within each of the four experiments. It was made without the creation of a spark. Furthermore, within these experiements the LED did not turn on at all. This was because, on its own no current passed through the Coherer device. Proving, that the spark is soley responsible on its own for turning on the LED. In conclusion, it shows that the spark was needed in order to turn on the LED and let current pass through the Coherer device.

Conclusion

To sum up, this scientific project highlights the importance of the location of where the spark is as it in turn decides whether the LED will successfully turn on or not. Moreover, in the scientific experiments' test results, the LED successfully turned on ALL the time when the spark was located above the Coherer device. Meanwhile, when the spark was located beside the Coherer device it didn't work as well as the LED only turned on a few times. Even more than that, it can be seen when the spark was located underneath the Coherer device it didn't work at all showing the worst test results as the LED didn't turn on at all. Moreover, when no current passed through the Coherer device, within the control group the LED didn't turn on at all showing the spark is needed to allow the Coherer device to become conductive. Furthermore, this shows how the positioning of the spark affects whether the LED turns on or stays off as well as if the control group works or not. This is because, when the spark was above it had no obstacles to pass but when the spark was moved beside or underneath it did have obstacles to overcome which made it harder to have enough electricity and current to turn on the LED. Therefore, as it can be seen the best location of the spark was above the Coherer device as the LED turned on in all tests and didn't flicker at all.

Application

This scientific experiment can eventually be applied to replace the transistors of today's world this would help upgrade to new modern-day computers from the computers of the world, today. This needs to be done sooner or later because Moore's Law is slowly and gradually coming to an end. Moore's Law states that the components on a microchip will double every two years. Therefore, the speed at which computers are upgrading is gradually slowing down. This is negative and unadvisable because people rely on using computers today for multiple different reasons, such as: programmers/coders, metrologists (to know the weather), scientists (to simulate things), etc. So, overall using the Coherer Effect as a transistor could later help in the future.

Sources Of Error

The sources of error within this scientific experimental project includes the following: static electricity, lightining, as well as the position of the aluminum ball within the Zap-it. Static electricity is a source of error because, due to the fact that our Coherer device turns on when their's a spark this means the static electrity can turn on the LED by creating a spark or a electrical discharge on its own. Lightining would also be considered a source of error because, it is similar to static electricality but it creates a bigger spark or electrical discharge on its own. The metal aluminum balls which was placed within the Zap-it is another source of error because, due to the fact we cannot control its location this could make each spark different in terms of their voltage.

Acknowledgement

Acknowledgments:

  • Grammarly was used for spell check.
  • Dad for helping understand some topics and set it up.
  • Mom for buying the neccessary materials.