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{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter 16: Oscillators"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 16.1: Wien_bridge_oscillator.sce"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"//ex16.1\n",
"R1=10*10^3;\n",
"R2=R1;\n",
"R=R1;\n",
"C1=0.01*10^-6;\n",
"C2=C1;\n",
"C=C1;\n",
"R3=1*10^3;\n",
"r_ds=500;\n",
"f_r=1/(2*%pi*R*C);\n",
"disp(f_r,'resonant frequency of the Wein-bridge oscillator in Hertz')\n",
"//closed loop gain A_v=3 to sustain oscillations\n",
"A_v=3;\n",
"//A_v=(R_f+R_i)+1 where R_i is composed of R3 and r_ds\n",
"R_f=(A_v-1)*(R3+r_ds);\n",
"disp(R_f,'value of R_f in ohms')"
]
}
,
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 16.2: Phase_shift_oscillator.sce"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"//ex16.2\n",
"A_cl=29; //A_cl=R_f/R_i;\n",
"R3=10*10^3;\n",
"R_f=A_cl*R3;\n",
"disp(R_f,'value of R_f in ohms')\n",
"//let R1=R2=R3=R and C1=C2=C3=C\n",
"R=R3;\n",
"C3=0.001*10^-6;\n",
"C=C3;\n",
"f_r=1/(2*%pi*sqrt(6)*R*C);\n",
"disp(f_r,'frequency of oscillation in Hertz')"
]
}
,
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 16.3: FET_Colpitts_oscillator.sce"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"//ex16.3\n",
"C1=0.1*10^-6;\n",
"C2=0.01*10^-6;\n",
"L=50*10^-3; //in Henry\n",
"C_T=C1*C2/(C1+C2); //total capacitance\n",
"f_r=1/(2*%pi*sqrt((L*C_T)));\n",
"disp(f_r,'frequency of oscillation in Hertz when Q>10')\n",
"Q=8; //when Q drops to 8\n",
"f_r=(1/(2*%pi*sqrt((L*C_T))))*sqrt((Q^2/(1+Q^2)));\n",
"disp(f_r,'frequency of oscillation in hertz when Q=8')"
]
}
,
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 16.4: Triangular_wave_oscillator.sce"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"//ex16.4\n",
"R1=10*10^3;\n",
"R2=33*10^3;\n",
"R3=10*10^3;\n",
"C=0.01*10^-6;\n",
"f_r=(1/(4*R1*C))*(R2/R3);\n",
"disp(f_r,'frequency of oscillation in hertz')\n",
"//the value of R1 when frequency of oscillation is 20 kHz\n",
"f=20*10^3;\n",
"R1=(1/(4*f*C))*(R2/R3);\n",
"disp(R1,'value of R1 in ohms to make frequency 20 kiloHertz')"
]
}
,
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 16.5: Sawtooth_VCO.sce"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"//ex16.5\n",
"V=15;\n",
"C=0.0047*10^-6;\n",
"R3=10*10^3;\n",
"R4=R3;\n",
"R2=10*10^3;\n",
"R1=68*10^3;\n",
"R_i=100*10^3;\n",
"V_G=R4*V/(R3+R4); //gate voltage at which PUT turns on\n",
"V_p=V_G; //neglecting 0.7V, this the peak voltage of sawtooth wave\n",
"disp(V_p,'neglecting 0.7V, this the peak voltage of sawtooth wave in volts')\n",
"V_F=1; //minimum peak value of sawtooth wave\n",
"V_pp=V_p-V_F;\n",
"disp(V_pp,'peak to peak amplitude of the sawtooth wave in volts')\n",
"V_IN=-V*R2/(R1+R2);\n",
"f=(abs(V_IN)/(R_i*C))*(1/(V_pp));\n",
"disp(f,'frequency of the sawtooth wave')\n",
"T=1/f;\n",
"xtitle('Sawtooth voltage controlled oscillator')\n",
"x=[];\n",
"for t=0:1*10^-5:4*10^-3 \n",
" tcor = t- floor(t/T)*T;\n",
" x_temp = (V_pp/T)*tcor + 1;\n",
" x = [x, x_temp];\n",
" end;\n",
" t=0:1*10^-5:4*10^-3\n",
" plot(t,x)"
]
}
,
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 16.6: 555_timer.sce"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"//ex16.6\n",
"R1=2.2*10^3;\n",
"R2=4.7*10^3;\n",
"C_ext=0.022*10^-6;\n",
"f_r=1.44/((R1+2*R2)*C_ext);\n",
"disp(f_r,'frequency of the 555 timer in hertz')\n",
"duty_cycle=((R1+R2)/(R1+2*R2))*100;\n",
"disp(duty_cycle,'duty cycle in percentage')"
]
}
],
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"language": "scilab",
"name": "scilab"
},
"language_info": {
"file_extension": ".sce",
"help_links": [
{
"text": "MetaKernel Magics",
"url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
}
],
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|
