Schema 1 kHz signal generator
Schema signal generator:
e small electronic assembly will be very useful in the lab of electronics even confirmed: despite its small
size and low cost, it will allow you to check the power of the answer in square sortieou an amplifier signal, to see the oscilloscope frequency response of a filter or control a CMOS counter, etc. The wiring diagram As shown in Figure 1, the heart is the integrated circuit 555, a timer ("Timer") can work, according configuration, monostable or astable multivibrator. In the application described here, it operates in the astable: the chip produces a square wave, instead of square, as its duty cycle is 50%. The working frequency (1000 Hz exactly) strongly depends on the values of R7 and C3, while the ratio between R1 and R3 determines the pause duration and pulse waveform. The signal out of the spindle 3 and reaches the output "square wave" (J1) using the resistive bridge formed of R8 and R2 inserted in order to limit to about 1.5V amplitude signal to the " buffer "(buffer) output. The pin 3 of the "timer", the basic rectangular wave reaches C7, which provides decoupling with respect to the continuous and provides an AC voltage or bi-directional (with positive and negative values with respect to ground) : this trick is used to get the other waveforms. Note that even the square wave is made bidirectional: you will find out by analyzing the output buffer, in which is another capacitor in series with the hot wire. What comes out of C7 is immediately filtered by C4, then passes through a first low-pass filter consisting of R4 and C5: the cut-off frequency thereof is about 330 Hz, which is low enough for obtaining, at the terminals of C5, a voltage exponential waveform (actually a wave composed of alternating growing exponentially traits with decreasing exponential). It is sent to the selection jumper (J2) so that it can eventually reach the output buffer. This same wave passes through another low-pass filter, identical to the previous (and therefore same cutoff frequency) which draws a triangular signal composed of relatively straight and falling ramps: it also reaches the line selection jumpers (J3).
The last filter, still consisting of a resistor 10 kilohms and a capacitor of 47 nF, provides a sine wave by integrating the triangular. The sinusoid is certainly not perfect, but it is rather like an ideal sine wave so that you can achieve without problem most lab measurements. On the other hand, in many waveforms generators based on specific integrated circuits (e.g. MAX038 or XR2206) the sine wave is obtained by integrating a triangular by means of active circuits comprising networks R / C . It is precisely to improve the quality sine wave is passed through a stage transistors amplifies not only in power but also in power, to prevent the load represented by the output buffer can negatively influence the chain of low-pass filters and cause unacceptable deformation of the waveform. The amplified sinusoidal component is levied on the circuit, is easily adjusted with RV1 trimmer mounted potentiometer. Between the OUT point and the ground, you can connect an RCA jack "Cinch" or BNC on which you take the signal to send to the device under test.
Figure 2b: Drawing to scale 1, the
circuit board of the generator
signals. List of electronic components: R1 ........ 1 k R2 ........ 1 k R3 ... ..... 1 k R4 ........ 10 kW R4 ........ 10 kW R5 ........ 10 kW R6 ........ 10 kW R7 ........ 15 kW R8 ........ 4.7 kW R9 ........ 100 kW R10 ...... 100 kW R11 .... ..1 MΩ RV1 ...... 50 kW C1 ........ 10 nF ceramic C2 ........ 10 nF ceramic C3 ........ 47 nF ceramic C4 ........ 47 nF ceramicC5 ........ 47 nF ceramic C6 ........ 47 nF ceramic C7 multilayer ........ 100 nF C8 .. ...... 1 uF 50 V electrolytic C9 ........ 1 uF 50 V electrolytic D1 ........ 1N4007 T1 BC547 ........ T2 .... .... BC547 IC1 ....... 555 Miscellaneous: 1 .. support 2 x 4 1 v battery door .. 4 .. full riders (parts stationary and moving part) two pins .. 3 .. screw tapping
Figure 1: Diagram of the signal generator.
e small electronic assembly will be very useful in the lab of electronics even confirmed: despite its small
size and low cost, it will allow you to check the power of the answer in square sortieou an amplifier signal, to see the oscilloscope frequency response of a filter or control a CMOS counter, etc. The wiring diagram As shown in Figure 1, the heart is the integrated circuit 555, a timer ("Timer") can work, according configuration, monostable or astable multivibrator. In the application described here, it operates in the astable: the chip produces a square wave, instead of square, as its duty cycle is 50%. The working frequency (1000 Hz exactly) strongly depends on the values of R7 and C3, while the ratio between R1 and R3 determines the pause duration and pulse waveform. The signal out of the spindle 3 and reaches the output "square wave" (J1) using the resistive bridge formed of R8 and R2 inserted in order to limit to about 1.5V amplitude signal to the " buffer "(buffer) output. The pin 3 of the "timer", the basic rectangular wave reaches C7, which provides decoupling with respect to the continuous and provides an AC voltage or bi-directional (with positive and negative values with respect to ground) : this trick is used to get the other waveforms. Note that even the square wave is made bidirectional: you will find out by analyzing the output buffer, in which is another capacitor in series with the hot wire. What comes out of C7 is immediately filtered by C4, then passes through a first low-pass filter consisting of R4 and C5: the cut-off frequency thereof is about 330 Hz, which is low enough for obtaining, at the terminals of C5, a voltage exponential waveform (actually a wave composed of alternating growing exponentially traits with decreasing exponential). It is sent to the selection jumper (J2) so that it can eventually reach the output buffer. This same wave passes through another low-pass filter, identical to the previous (and therefore same cutoff frequency) which draws a triangular signal composed of relatively straight and falling ramps: it also reaches the line selection jumpers (J3).
Figure 2a: Installation diagram
generator components
signals.
The last filter, still consisting of a resistor 10 kilohms and a capacitor of 47 nF, provides a sine wave by integrating the triangular. The sinusoid is certainly not perfect, but it is rather like an ideal sine wave so that you can achieve without problem most lab measurements. On the other hand, in many waveforms generators based on specific integrated circuits (e.g. MAX038 or XR2206) the sine wave is obtained by integrating a triangular by means of active circuits comprising networks R / C . It is precisely to improve the quality sine wave is passed through a stage transistors amplifies not only in power but also in power, to prevent the load represented by the output buffer can negatively influence the chain of low-pass filters and cause unacceptable deformation of the waveform. The amplified sinusoidal component is levied on the circuit, is easily adjusted with RV1 trimmer mounted potentiometer. Between the OUT point and the ground, you can connect an RCA jack "Cinch" or BNC on which you take the signal to send to the device under test.
Figure 2b: Drawing to scale 1, the
circuit board of the generator
signals. List of electronic components: R1 ........ 1 k R2 ........ 1 k R3 ... ..... 1 k R4 ........ 10 kW R4 ........ 10 kW R5 ........ 10 kW R6 ........ 10 kW R7 ........ 15 kW R8 ........ 4.7 kW R9 ........ 100 kW R10 ...... 100 kW R11 .... ..1 MΩ RV1 ...... 50 kW C1 ........ 10 nF ceramic C2 ........ 10 nF ceramic C3 ........ 47 nF ceramic C4 ........ 47 nF ceramicC5 ........ 47 nF ceramic C6 ........ 47 nF ceramic C7 multilayer ........ 100 nF C8 .. ...... 1 uF 50 V electrolytic C9 ........ 1 uF 50 V electrolytic D1 ........ 1N4007 T1 BC547 ........ T2 .... .... BC547 IC1 ....... 555 Miscellaneous: 1 .. support 2 x 4 1 v battery door .. 4 .. full riders (parts stationary and moving part) two pins .. 3 .. screw tapping
Figure 3: Photograph of a prototype
the signal generator
