• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

There are many different components that would be needed in order to produce or construct a Random number generator or in this case the Electronic Die.

Extracts from this document...

Introduction

Research

There are many different components that would be needed in order to produce or construct a Random number generator or in this case the Electronic Die.

COMPONENTS

Although knowledge of the details of the construction of components is not required by the syllabus, there are occasions when such knowledge will help with an understanding of how the components works.  When this is felt to be the case, details of construction are included below for information.

Apart from the actual value of a component, there are four other factors to consider when selecting a component for a circuit.

  1. The physical size of the component.  Some applications demand miniature components, e.g. mobile phones.  The use of Surface Mounted Devices (SMDs) is essential in such applications, while the use of leaded components is often more useful in circuits like wshing machine controllers, where space is not important.
  1. The cost of the components.  Very cheap components should not be used if it is likely to affect the reliability of the electronic system, especially in critical applications e.g. The Engine Management Units in cars!
  1. The power rating of the component.  Whenever a current passes through a component that has resistance, power is dissipated and the component will become hot.  It is important when selecting components to ensure that the component is able to withstand more
...read more.

Middle

image09.png

To calculate the value of the series resistor it is first necessary to decide on the current that should flow through the LED.  The data sheet for the LED will specify a maximum current Imax.  The LED current should be less than this.  If the supply voltage is Vs, then

Vs – 1.8

            R =           Imax

The minimum value used for R should be the next largest preferred value.

LEDs are used as indicator lamps and in seven-segment displays.  They have the advantages of small size, long life, a small operating current and high operating speed.  There is now a large range of different LEDs available with outputs ranging from the infrared to blue wavelights.

Seven segment array

Electronic calculators, clocks, cash registers and measuring instruments often have seven-segment LED displays as numerical indicators.  Each segment is an LED and by lighting up different segments all numbers from 0 to 9 can be displayed.  Each segment needs a separate current limiting resistor to prevent damage to the segment by excess power dissipation.

All the cathodes (common cathode type) or all the anodes (common anode type) are joined to form a common connection.  If the driving circuit is made from transistors, so that the seven-segment display segments are connected in the collector circuits, then a common anode Figure ____ display will be required.

Seven segment Display

...read more.

Conclusion

The RESET terminal can be used to set the output to 0V at any time by being connected momentarily to 0V.  Normally, the RESET terminal is connected to Vs to prevent any spurious resetting of the output.The CONTROL terminal is connected to the 2/3 Vs point of the voltage divider and can be used to alter the voltage switching levels of the comparators.  Normally it is decoupled by a 10nF capacitor connected to 0V.image00.png

image04.png

image06.png

image02.pngimage01.pngimage02.pngimage07.pngimage02.pngimage02.png

                    The 555 astableimage05.pngimage03.png

The common circuit for a 555 astable is shown in figure

When first switched on the capacitor, C, is discharged and so the voltage across this capacitor is less than the TRIGGER voltage and so the output goes to Vs.  The capacitor, C, charges through R1 and R2 until the voltage across C is greater than the THRESHOLD switching level, at which point the output voltage becomes 0V and the DISCHARGE terminal becomes connected to 0V.

The capacitor now discharges through R2 until the voltage across C becomes less than the TRIGGER switching voltage.  When this happens, the output voltage becomes Vs and the process repeats.  It should be noted that the first pulse is longer than the remainder, since C has to charge from 0V and not 1/3 Vs.  The same restrictions apply to the values of C and R (R1 and R2) as for the monostable.

...read more.

This student written piece of work is one of many that can be found in our AS and A Level Electrical & Thermal Physics section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Electrical & Thermal Physics essays

  1. Marked by a teacher

    Determining Avogadro's Number Lab

    4 star(s)

    and an anode (Electrode 2). In the anode, one atom is ionized and dissolved into the solution from the anode for every copper atom is deposited on the cathode. The gain or loss of mass of each electrode can then be divided into the molar mass of copper, which will then equal the number of moles of reacted copper.

  2. Peer reviewed

    Test of the reed switch capacitors in series and in parallel

    3 star(s)

    V = 4.55V Measured current I = 0.4mA Therefore, theoretical current I = CVf = (0.22x10-6)(4.55)(400) = 0.4004mA Capacitors in series The results were recorded as shown as below: Capacitance C1 = 0.22�F Capacitance C2 = 0.22�F Equivalent capacitance Ceq = (1/ 0.22 x10-6+1/ 0.22 x10-6)-1 = 0.11�F Frequency f = 400Hz P.d.

  1. Using an LDR to detect the intensity of plane polarised light allowed through a ...

    The formula states that the amount of light let through (transmitted by) the polaroid is equal to the amount of light which collides with the polaroid, multiplied by the square of the cosine of the angle between the angle of the direction of polarisation of the wave, and the preferred plane of the polaroid.

  2. Characteristics of Ohmic and Non Ohmic Conductors.

    As we can see here the current does not exceed 1 A and thus the prediction is that it should form a linear graph because the resistance is almost constant and so this proves that there was no heating effect.

  1. Find The Internal Resistance Of A Power Supply

    that the power supply can deliver which has been extrapolated from the results by extending the average gradient line. The internal resistance values have been got from the average gradient values in graphs 3 to 7 and then a mean average value has been calculated.

  2. Current rating of fuses and MCB's.

    In this practical the fusing factor was . This value is rather high. However the value might not be the exact fusing factor of the fuse used due to the errors that are present in the practical. MCBS Circuit symbol: The MCB has several advantages over fuses which have been

  1. Study of capacitors in charging And discharging processes 1

    I?C or Q?C ii) The voltage across the capacitors: Refer to the second table, with unchanged capacitance of capacitors, it was found that C=2.67V (1.5/4, 3/8...). As a result, the voltage across the capacitors was found to be directly proportional to the current.

  2. Sensors cwk. The aim of this coursework is to construct a potential divider circuit ...

    The resulting free electrons conduct electricity, thereby lowering resistance. The device can be either intrinsic or extrinsic. In intrinsic devices, the only available electrons are in the valence band, and hence the photon must have enough energy to excite the electron across the entire bandgap.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work