Function Generator essays

Function Generator essays Purpose: The purpose of this experiment is to construct a function generator capable of taking a DC input and producing different outputs. The three desired outputs are a sinusoidal wave, a square wave, and a triangle wave. The function generator should also include a DC offset adjustment as well as amplitude control for the output waveform. Components to be used: DC power supply ( +15 Volts), 3 1N4148 diodes, one LED, 4 741 op-amps, 3 0.01 micro-farad capacitors, 2 1 micro-farad capacitors, 1k-ohm resistor, 2.2k-ohm resistor, 8.2k-ohm resistor, 10k-ohm resistor, 1 ganged 10k-ohm potentiometer, 2 10k-ohm potentiometers, 15k-ohm resistor, 2 18k-ohm resistor, 100k-ohm potentiometer. 1. Construct the Wein-bridge oscillator as shown in figure 1. Test output point A for sine wave, adjust potentiometers to change amplitude and frequency. 2. Construct the Schmitt trigger shown in figure 2. Connect input point A to output point A. Test output point B on the Schmitt trigger, the output should be a square wave. 3. Construct the integrator shown in figure 3. Connect input point B to output point B. Test output point C on the integrator, the output should be a triangle wave. 4. Construct the circuit shown in figure four. Adjust the potentiometer to adjust the DC offset. Discussion of Results: By following the above procedure, you should develop the desired function generator. The end result should match figure 5. Along the way a couple of problems were encountered. First, by using a 741 op-amp in the second stage (Schmitt trigger), a perfect square wave could not be obtained. By substituting a 318 op-amp it corrected the problem. The 318 gave a cleaner output because of its higher slew rate. The other problem occurred in the third stage, the integrator. The output of this stage using the called for capacitor (0.047 micro-farads) gave a distorted output. By adding a ...