Do you have a square waveform generator, but not a real pulse generator for testing the integrator_ here is a simple (crude) way to get the pulse you need. – ppt download

Do you have a square waveform generator, but not a real pulse generator for testing the integrator? Here is a simple (crude) way to get the pulse you need — about 1 millisecond long, 1-5 volts high, 50 pulses each second. Pulse width modulation using 555 timer theory It generates a more-or-less square pulse on every rising edge of the input square wave. Pulse width modulation inverter circuit diagram Adjust… Pulse width modulation motor speed control –the repetition rate by the waveform generator’s frequency (50 Hz) –the width of the output pulse by the waveform generator’s amplitude (low) –the amplitude of the output pulse using the 10K pot 10K ? 0.1 ? F 1N914 10K ? pot 10K ? input impedance + – INTEGRATOR SQUARE WAVE IN Believe me when I tell you that this turkey will not be found in any book of standard circuits; it’s a “make do with what you’ve got” sort of kludge. Pulse width modulation stepper motor A TTL one-shot (e.g ) is a better way to go if you’ve got one. Types of pulse width modulation A waveform generator chip is even better. Pulse width modulation advantages The first capacitor and resistor differentiate the square wave, producing short up-going and down-going pulses. Pulse width modulation and demodulation experiment theory The first diode removes the down-going pulses. Introduction to pulse width modulation The op-amp, highly saturated, is usually at -15 V but rushes to +15 V when the incoming pulse shows up. Pulse width modulation for power converters principles and practice ebook The 10K pot voltage divides the output to get a reasonable (and adjustable) pulse height. Pulse width modulation dc motor speed control The final diode keeps only the positive portion of the output pulse. Pulse width modulation dimmer 741 op-amp 1

Here is a better pulse generator based on the 74LS123 dual one-shot (only one one-shot is used).


Pulse width modulation speed control of dc motors The input is a square wave, about 3 volts peak-to-peak, at the desired pulse repetition rate (e.g Hz). Pulse width modulation control theory The outgoing pulse width is variable between about 0.1 ms and 3.5 ms, and the outgoing pulse height is variable from 0 volts to about 3 volts — plenty of variation to give the voltage integrator a good workout. Pulse width modulation led 1N914 10K ? 2 Integrator amplitude adjustment GND B IN V A IN 10K ? V CC 16 74LS K ? 0.1 ? F C EXT RC EXT pulse width adjustment Q OUT 13 ~3 V peak-to-peak ~40 Hz The 74LS123 is powered by +5 volts (pin 16) and ground (pin 8). Theory of pulse width modulation Do not connect +15 V or -15 V to this chip! Set the two pots to about midrange and the input waveform generator to low amplitude. Pulse width modulation control circuit Power up. Pulse width modulation power supply Increase the waveform generator’s amplitude until you see output pulses, but don’t go beyond about 4 volts peak-to-peak on the input. Pulse width modulation converter Adjust the two pots to get the output pulse width and amplitude that you need to exercise the voltage integrator. What is pulse width modulation used for not connected connected 2

The Leaky Voltage Integrator The upper trace is the incoming pulse to be integrated. Pulse width modulation using 8051 microcontroller Its amplitude is very small. Pulse width modulation circuit The lower trace is the output of the integrator. Pulse width modulation inverter You can see it growing (downward) during the input pulse, and discharging (leaking) during the long wait until the next input pulse. Advantages of pulse width modulation Two questions: 1. Pulse width modulation vhdl code Is the leak so large that it has a significant impact on the accuracy of the integration? Remember that the leaking doesn’t stop during the input pulse. Single pulse width modulation pdf 2. Pulse width modulated dc dc power converters marian k kazimierczuk Is the integrator’s capacitor adequately discharged before the next pulse arrives? V OUT 3

Since no current flows in or out of the op-amp input terminals, the current I through R 1 must be the same as the current through R 2. Pulse width modulation project I = V/R for both resistors. How pulse width modulation works Hence [1] (V OUT – V IN- ) / R 2 = (V IN- – V SRC ) / R 1 Multiplying by R 1 R 2… Pulse width modulation for power converters principles and practice [2] R 1 (V OUT – V IN- ) = R 2 (V IN- – V SRC ) Expanding… Pulse width modulation techniques [3] R 1 V OUT – R 1 V IN- = R 2 V IN- – R 2 V SRC [4] By definition, the open-loop gain of the op-amp is G OL = -V OUT / V IN- (with V IN+ at ground) so V IN- = -V OUT / G OL. Simple pulse width modulation circuit Substituting for V IN- in [3]… Pulse width modulation using op amp [5] R 1 V OUT + R 1 V OUT / G OL = -R 2 V OUT / G OL – R 2 V SRC Multiplying by G OL and collecting terms with V OUT… Pulse width modulation applications [6] R 1 G OL V OUT + R 1 V OUT + R 2 V OUT = -R 2 V SRC G OL [7] V OUT = -V SRC R 2 G OL / (R 1 G OL + R 1 + R 2 ) which for very large G OL becomes just V OUT = -V SRC (R 2 / R 1 ). Pulse width modulation vhdl In the general case, the two equations in red, [7] then [4], will yield V OUT and V IN- given V SRC, G OL, R 1 and R 2. Pulse width modulation lab experiment [8] It is useful to define the actual gain of the entire circuit G CIRC = -V OUT / V SRC = R 2 G OL / (R 1 G OL + R 1 + R 2 ) (from [7]) Inverting… Pulse width modulation raspberry pi [9] 1 / G CIRC = (R 1 G OL + R 1 + R 2 ) / R 2 G OL = R 1 / R 2 + R 1 / R 2 G OL + 1 / G OL [10] We can define the ideal (very large G OL ) gain of the amplifier as G IDEAL = R 2 /R 1. Led pulse width modulation Multiplying [9] by G IDEAL… Advantages and disadvantages of pulse width modulation [11] G IDEAL / G CIRC = / G OL + G IDEAL / G OL = (G OL + G IDEAL + 1) / G OL. Pulse width modulation amplifier [12] G CIRC = G IDEAL ? G OL / (G OL + G IDEAL + 1) In words, the actual gain of the amplifier is the ideal gain R 2 /R 1 multiplied by a correction factor that is nearly 1 for op-amps with very large open- loop gains but becomes significantly less than 1 as the op-amp gain becomes comparable to the ideal gain. Pulse width modulation for power electronic converters Clearly you can reach the troublesome region where the correction factor is significantly less than 1 by (1) operating the op-amp in a frequency regime where its open-loop gain is low, or (2) demanding that the gain of your amplifier be very high, or (3) even worse, both. Pulse width modulation formula Calculating the Basic Properties of the Inverting Amplifier 4

What is the effect on a feedback-controlled inverting amplifier if the op-amp does not have a very high open-loop gain? Let’s consider the inverting amplifier (circuit #1). Pulse width modulation advantages and disadvantages R1 — the input resistor (e.g. Unipolar pulse width modulation 10 K) R2 — the feedback resistor (e.g. Pulse width modulation adalah 100 K) V SRC — the voltage at the input to the circuit (referenced to ground) V IN- — the voltage at the inverting input of the op-amp (referenced to ground since V IN+ is at ground) V OUT — the voltage at the op-amp (hence circuit) output (referenced to ground) G OL — the open-loop gain of the op-amp ? -V OUT / V IN- for V IN+ at ground G CIRC — actual circuit gain ? -V OUT / V SRC for V SRC and V OUT referenced to ground If we define the ideal gain of the amplifier to be G IDEAL = R2 / R1 and substitute this into eqn. Define pulse width modulation 1, then G CIRC = G IDEAL x G OL / ( G OL + G IDEAL + 1) For high G OL, the correction factor relating the actual and ideal circuit gains is nearly one. Pulse width modulation thermostat As G OL gets lower, approaching G IDEAL, the correction factor starts falling significantly below 1, so the real circuit gain becomes less than the feedback-defined ideal gain. Pulse width modulation and demodulation experiment Noting that no current flows in or out of the V IN- terminal, we can compute the current through R1 and R2: I = (V OUT – V SRC ) / (R1 + R2) and the voltage drop across R2: (V OUT – V IN- ) = I ? R2. Wiki pulse width modulation As defined above, V OUT = -G OL V IN- ; V IN- = -V OUT / G OL After a few lines of algebra : G CIRC ? -V OUT / V SRC = R2 / [ R1 + (R1 + R2) / G OL ] eqn. Pulse width modulation diagram 1 For G OL very large, (R1 + R2) / G OL is very small compared to R1, so G CIRC ? R2 / R1 As G OL becomes smaller, the full formula must be used; the denominator increases so |G CIRC | becomes smaller. Operation of pulse width modulation 5

Minimum Circuit for Sine and Triangle Waves — EXAR XR-2206 Waveform Generator +15 V GND Vcc STO AMSI 1 MO TC1 TC2 TR1 TR2 FSKI SYNCO WAVEA1 WAVEA2 SYMA1 SYMA2 11 x 10K 0.1uF SINE or TRIANGLE WAVE OUT 200 x x x BIAS 10 1uF SQUARE WAVE OUT Timing capacitor C T uF to 100 uF 5.1K 1.0uF +15 V 10K Timing resistor R T 1K ? to 2M ? Remove resistor for triangle wave output RTRT CTCT Frequency 1 / R T C T Here F = 1 / (10 4 ? ) = 1KHz +15 V 1uF Smooth internal bias voltage Smooth Vcc Sine wave is centered at about this voltage, here ~7.5 volts Determines amplitude of sine wave, here ~1.6 volts peak-to-peak 0 to 50K ? Pullup resistor for open collector square-wave output Frequency determined by R T and C T Offset and amplitude determined by pin-3 circuitry Frequency determined by R T and C T Varies between ~ground and ~pullup voltage 6

Embellished Circuit for Sine and Triangle Waves — EXAR XR-2206 Waveform Generator +15 V GND Vcc STO AMSI 1 MO TC1 TC2 TR1 TR2 FSKI SYNCO WAVEA1 WAVEA2 SYMA1 SYMA2 11 x 50K SINE or TRIANGLE WAVE OUT 500 x BIAS 10 1uF SQUARE WAVE OUT Switch in various capacitors between uF to 100 uF 5.1K +15 V 10K 1K ? Make R T continuously variable between 1K ? and 2M ?. Multiple pulse width modulation You must not let R T fall below 1K ? ! ! Sine waveform adjustment. Pulse width modulation for power converters pdf Open switch for triangle waves. Pulse width modulation definition RTRT CTCT Frequency 1 / R T C T +15 V 1uF Smooth internal bias voltage Smooth Vcc Provide some adjustment for the sine wave’s offset voltage. Pulse width modulation circuit for hho Remember that moving this away from the midpoint voltage (7.5 volts) reduces the maximum sine wave amplitude. Pulse width modulation inverter pdf 1.0uF Make this a 0-50K ? variable resistor for amplitude control Pullup resistor for open collector square-wave output Frequency determined by R T and C T Offset and amplitude determined by pin-3 circuitry Frequency determined by R T and C T Varies between ~ground and ~pullup voltage ? 2M ? 1K Waveform symmetry adjustment. Pwm pulse width modulation definition 25K 7

Leave a Reply

Your email address will not be published. Required fields are marked *