## Electronics : Intermediate

Study circuits that deal with electronic devices such as diodes, transistors, and operational amplifiers.

## Electronics : Filters and analysis

Characterize Op-Amp based filters by plotting their frequency and phase response

Record a sound source and analyze its quality

## Electronics : Fundamentals

Tutorials to get acquainted with basic concepts in electronics. Targeted at absolute beginners.

And many more such applications that touch upon various phenomena such as EM induction , and electrochemical cells from household objects

## BJT as an amplifier

Learn to use a BJT as an amplifier in the common emitter configuration. The GUI for this is located at Electronics -> Transistor -> Transistor amplifier

The input and output waveforms are traced on the oscilloscope using two channels. The gain can be calculated directly using the measure gain button. This experiment can be modified to calculate the bandwidth of the amplifier by varying the frequency of the input waveform and noting the corresponding gains as a function of the frequency.

Resultant Data:

``````from SEEL import interface
I=interface.connect()

#fetch 5000 points each from CH1, CH2 with 2uS between each
x,y1,y2 = I.capture2(5000,2)

from SEEL.analyticsClass import analytics
math = analytics()
amp1,freq,phase,offset = math.sineFit(x,y1) #Calculate parameters of input waveform
amp2,freq2,phase2,offset2 = math.sineFit(x,y2) #calculate parameters of output
print (amp1,amp2,'gain = %.3e'%(amp2/amp1)) #calculate and print gain

from pylab import *
plot(x,y1)
plot(x,y2)
show()``````

## Output characteristics of a Bipolar Junction Transistor (BJT)

Launch BJT Output Characteristics GUI from SEELablet – > Electronics -> Transistors -> Transistor CE

Prepare the experiment based on the schematic and instructions available in the help section.

Resultant Data:  The base voltage (thereby base current) is varied and the corresponding I-V curves are plotted.

``````from SEEL import interface
I=interface.connect()

pv2 = I.set_pv2( 1.0)   #  Bias the base via a 200K resistor.
base_voltage = I.get_voltage('CH3')
base_current = (pv2-base_voltage)/200e3 # Use Ohm's law to determine current
CollectorCurrent = []
CollectorVoltage = []
for a in np.linspace(0,5,100):
pv1 = I.set_pv1(a)
CollectorCurrent .append( (pv1 - I.get_voltage('CH1') )/1e3 )
CollectorVoltage.append(pv1)

from pylab import *
plot(CollectorVoltage,CollectorCurrent ) #Plot and try a different base current
show()``````

## Electronics Experiments example: Studying a linear amplitude modulator circuit

Analog multiplier ICs such as the AD633 are used for communication applications such as amplitude modulation.

Using the sine wave generators and the oscilloscope of the SEELablet, they can be studied

W2 is used as the carrier, and was set to 4987.5 Hz. W1 was set to 402 Hz , and used as the modulating input. The fourier transform of the modulated output clearly shows that sidebands are formed at frequency(carrier) +/- frequency (modulator)

The utility can be launched from SEELablet – > Electronics -> Communication -> amplitude Modulation

Fourier transform of the modulated output shows a single peak for the carrier, and sidebands with frequencies (carrier +/- modulator ) . Changing the modulation amplitude changes the height of the sidebands. In the figure, CH2 is connected to the modulation input.