Self Powered Sine to Square wave Converter by s0v3e3xV


									           Self Powered Sine to Square wave Converter.
Circuit Diagram:

R1                  1M 1/4W Resistor
R2                  100K Linear Potentiometer                          The capacitor C3 blocks any voltage due to the voltage doubler
C1,C2               100µF 25V Electrolytic Capacitors                  circuit hence allowing only AC signal to pass through
C3                  10nF 63V Polyester Capacitor
D1,D2               1N4148 75V 150mA Diodes
IC1                 4069 Hex Inverter IC.

The Self powered Sine to Square wave converter is intended to
                                                                                               High Input Impedance.
provide good square waves converting a sine wave picked up from
an existing generator. Its main feature consists in the fact that no
power source is needed, thus it can be simply connected between a      The above schematic is with reference to ICA. This amplifies the
sine wave generator and the device under test.                         input signal. The value R1=10M is replaced by 1M according to the
                                                                       amplification required. The resistor R1 also limits the gain of the

The above circuit converts a sine wave input into a square wave        IC4069 Hex Inverter:
with requirement of no power source. A voltage doubler is formed
by capacitors C1,C2 and diodes D1 and D2. The circuit makes use
of a Hex Inverter 4069 IC which is powered by the voltage
doubler. The ICA amplifies the input sine wave, other inverters
included in IC1 squaring the signal and delivering an output wave
of marks/space ratio and good rise and fall times through the entire
20Hz-20KHz range. The output square wave amplitude is
proportional to input amplitude.

Working of Voltage Doubler Circuit:

During the Positive half cycle of the input signal, diode D1 is
reverse biased, diode D2 is forward biased and the input voltage
charges the capacitor C2 up to peak rectified voltage (Vin)
During the negative half cycle of the input signal, diode D2 is        The circuit makes use of IC 4069 Hex Inverter of type CD4069UBE.
reverse and D1 is forward biased. Diode D1 is ideally short during     It consists of six CMOS inverter circuits.
this half cycle. By KVL, we get,                                       The driving voltages Vdd and Vss required for the working of the
                      Vin+Vc2-Vc1=0--------2.                          MOSfet is given by the voltage across the capacitor C2 as shown in
                           But Vc2=Vin.                                the circuit diagram.
                          Hence Vc1=2Vin

                                                                   In today's modern world, a square timing signal is the most basic
                                                                   signal required in a number of applications. Be it a basic 8085
                                                                   microprocessor or the modern day Pentium 4 processor all require a
                                                                   timing square wave pulse. As we all know, no natural oscillator can
                                                                   produce a square wave. All oscillators produce sine waves. Thus we
                                                                   require converting these sine waves into square waves before using.
                   Schematic of one inverter
Features of CD4069UBE:
     Standardized Symmetrical output characteristics.             Minimum sine wave input amplitude needed for good performance
     100% tested for quiescent current at 20V.                    is 750mV RMS
     Maximum input current of 1μAat 18Vover full package
         temperature range; 100nA at 18Vand 25ºC.

    Logic Inversion.
    Pulse shaping.
    Oscillators.
    High input impedance amplifiers.

The supply voltage range should be between 3V to 18V for
maximum reliability.

Maximum Ratings:

  D.C. supply voltage range referenced to Vss   -0.5V to +20V
        Input voltage range(All inputs)            -0.5V to

       D.C. input current, any one input           +10mA

       Operating temperature range(TA)             -55ºC to
        Storage temperature range(Tstg)            -65ºC to
      Lead temperature(During soldering)           +265ºC
  At a distance of (1.59 + 0.79mm.)from case
                   to 10s max


    1) Unlike the given circuit, the actual circuit needs high
       value for capacitor C2, because the IC consumes more
       current due to which capacitor cannot retain the charges
       stored in it and starts discharging. This eventually
       reduces the amplitude of the square wave in the output up
       to zero as the capacitor gets completely discharged. To
       rectify this up to some extent, we connected a capacitor
       of 100μF in parallel with C2 thus a total capacitance of
       200μF is used in the circuit
    2) The potentiometer should be set at maximum value to
       obtain a clear square wave output.

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