Electronic Components - Assignment Example

ELECTRONIC COMPONENTS Introduction. This laboratories main aim is to familiarize schematic entry & simulations by using the ISIS computer program and the investigation of some of the analogue electronic circuits available. Here we have managed to come up with electronic circuit technologies such as the full wave bridge rectifier, oscillator circuits, Wien bridge oscillator and the linear regulator and at the same time also monitoring the output signals from the oscillators. Definition. Wien Bridge Oscillator: It is an electronic component that uses RC high pass filter & an RC low pass filter in setting frequencies of oscillation while at the same time generating sine waves with absolutely no any source of input. LM714-op amp: It is an operational amplifier with multiple applications within it. It contains features such as the compensated internal frequency, offset null, voltage range with a high input, temperature stability and short circuit stability. Description. In the first part we have managed to develop the full wave rectifier circuit which is mainly used to convert AC to DC voltage. This circuit has been made possible by the aid of an ISIS computer software. Within the circuit, the bridge is connected to the input voltage of the AC and the other remaining two parts of the bridge are connected to the load. The capacitor is connected in parallel with the load because it must attenuate the ripple component of the voltage from the rectifier and at the same time it prevents the load voltage from falling to zero. How The Circuit Works. On the initial positive cycle within the input wave there are diodes D3 & D2 which are forward biased and diodes D1 & D4 which are reversed biased therefore current only flows from the diodes D3 & D2. This particular output will make the capacitor to be discharged. Now, in the negative half cycle, diodes D1 & D4 are forward biased and D2 & D3 will be reversed biased, this makes the current to flow only from diodes D1 & D4 and the output is similar to the curve on the graph shown below. In the second part, we will use 25V RMS supply with a ripple of 2V peak and 820 ohm load so as to apply the figures accordingly within the equation. and we get the value Iave =37.44 and C=187.2µF. In the third part we need to discuss the techniques of maintaining a stable voltage regardless of the current being withdrawn by the components. Here we will need 3 main components in order to achieve this state. 1. A precision reference (Zener Diode) which is mainly used in setting the output voltage. 2. A muscle component (Transistor) this will be used in delivering the desired current. 3. An automatic controller (Op amp) to aid in delivering the desired load current and at the same time maintaining the output voltage at a fixed figure. The Opamp is a very crucial element within electronic circuits and some of its notable features may include: It has a large forward transfer function. It has a wide band width with a very high gain (A=∞). It consists of a very large input impedance and this makes it very easy in applying various signals without loading (Z i=∞). It also at the same time has a small output impedance which makes the power supply by the op-amp unlimited. It is virtually non-existence. And these features go hand in hand with some of the rules pertaining to the op-amps which may include: The input circuit I1 and I are zero (Z in=∞) The voltage V1 and V are equalV1=V, so “A" should be a ∞ The phase rule will require a negative feedback and it is mainly used in the control and stabilization of the amplifiers gain. The open load gain sometimes becomes too big to be used and the noise carried causes the circuit to clip. In order to stabilize the amplifiers gain, the output will also be back to the input closed negative feedback load and this makes the closed loop gain entirely independent on the amplifiers characteristics. Within my circuit, Zener diodes application is achieving a uniform voltage across itself when the current passing through it is sufficient to drive it into the Zener breakdown region. Within my circuit which has been aided by using the ISIS computer application software, I have managed to establish the output circuit together with the output voltage. Within the circuit the Zener voltage is 5.1V which is half the output voltage of 10.3V and has a load current of 0.04mA. It is charged with a short connection for the load and the current on the ammeter is 73.4mA to discharge through the load provided that the time constant is not too short and the load voltage has not dropped significantly before the next charging pulse within the circuit. The Dc output of a full wave rectifier may be achieved if there is an assumption that the time constant is large enough for the entire capacitor voltage to be taken linear rather than exponential. According to the design of the rectifier circuit, we are going to calculate the capacitance within the observation and fix the supply voltage as 20Vrms, Vp=√2*Vrms so that we may achieve 28.28V. We may set the power supply amplitudes at 28.28 with a frequency of 50 hertz, the circuit rectifier is simulated within the graph and a ripples voltage value will be observed as 143V. The average current through load  And with the relationship with ripple voltage  This makes  And Therefore  2*1.43*50*c = (28.28-1.43/2-1.4)/100 And it could be argued that c=192.97µF.but actually in real sense it should be a200µF. If we would take the ripple voltage as 1.5 volts, the capacitance value would be the same as the report value, this would make the average current through the load as:  =2*1.43*50*192*97*10^-6 =26.16mA In a rectifier circuit with several components when we use supply voltage 25 V rms then  =35.35V The load resistance changes to 820we update the circuit and observe the ripple voltage on the graph. Part 4 An oscillator circuit that produces oscillation, the signal feedback from the output (Vo) must always be in phase with the input. The oscillation employs a series of parallel combination of both the resistors & capacitors for the feedback network. Oscillators that transform RF to IF signal within a receiver are mainly used in the application of digital clocks within systems and applied in sweep circuits within TV sets and the CRO. The frequency of the oscillator may be achieved by:  hear R=10k,c=10nF Therefore f= 1.6 kHz NB: Theoretical frequency is more than practical frequency. And amplifier gain must be 3 for oscillation therefore,  Part 4 Schmitt trigger Circuit. This is a comparator application that is mainly used to switch the output negative when the input passes upward through a positive reference voltage. It eventually will use a negative feedback to prevent going back to the other state until the input is through with a lower voltage hence stabilizing the switching against the rapid triggering by electrical noises as it goes through the trigger point. In a rectangular output wave form, the trigger simulation that will be used to convert the input wave form for the signals. The output voltage will be high if the input voltage is positive than the specified voltage then  And if the input voltage is less than the lower power threshold then  What gives rise to a hysteresis? In a layman’s point of view hysteresis may be explained as the condition when the input is absolutely higher that a certain threshold and the output are high. When the input are below the chosen threshold then the output is low and when the input is lying between the two then the output will ultimately retain its value. This trigger was eventually named so due to its principle of the output retaining its value until there is a change at the inputs sufficient to trigger a change. Now, it is very easy to eliminate noise within electrical signals, there may be noise with unwanted swings up to Va & Vb which could be zero and below. Because we have the frequency generator 1 kHz with amplitude 8V and Vl=-7.6V. Vi=+8V, one can be used as the lower level of the input while the other the higher level of output and where there is a simulating circuit of higher 2,R2=4.7k we will apply the sine generator to the input frequency of 1 kHz and amplitude 8V. With all this important informationit is possible to design the circuit with all the principles of a schematic trigger. Part 4-C Phase shift Oscillator. It is simply a sine wave electronic oscillator that contains an inverting amplifier & a built in feedback filter which automatically shifts the phase by 180 degrees within the oscillation frequency. The filter has to be designed in such a way that the frequencies above & below the oscillation frequency will make the signal to be shifted by more or less than 180 degrees. This eventually yields in constructive superposition of signals within the oscillation frequencies and destructive superposition for the remaining frequencies. One of the most popular ways used in the implementation of this particular filter is using a three cascaded resistor-capacitor filter which is not known to produce phase shifts at one end of the frequency scale and a phase shift of 270 degrees at the end. At oscillation frequencies, each of the filters present will produce phase shift of 60 degrees and hence the whole filter circuit will produce a phase shift of 180 degrees. Here I managed to design the RC phase shift oscillator that will perform alongside the frequency graph I have supplied. I have included a frequency graph to the sine generator on the horizontal axis and set the properties of the graph to run 1khz to 100khz in order to perform the simulation. The highly resonant at the frequency  Here R=1kΩ and c=10nF So the frequency f=6.4 KHz. Part 5. Here I have managed to design the Wien bridge oscillator circuit with values R4 100k and R3 200K. R3 is in series with 0.7 of 10k in order to increase the feedback gain. In the second part, +12 and -12 volt in DC generator were joined together and the amplifier signal was observed on the CRO and it was unchanged. Conclusion. In my practical assignment I have managed to understand some features of the proteus software and its simulation, I also managed to grasp some new knowledge on how some electronic basic components work such as the op-amp configuration. Read More