Hi All,
Software guy here who has developed an interest in hardware. I started with a RPI then an Arduino. Now I am starting working with basic discreet circuits and going analogue! Mind bending stuff. Not the precise 1's and 0's I am used to working with.
I am trying to get my arms around low and high pass filters with RC components. I have both a signal generator and new Rigol DS1054Z oscilloscope to help me through my learning curve.
To start, I built a circuit targeted at blocking signals above 310Hz using a 510Ohm resistor and a 1uF capacitor (electrolytic) . I built a first order and second order version of the circuit (see below) and then ran tests on the oscilloscope measuring the amplitude in V at different frequencies from 30 to 8K Hz. The results from the tests are below.
I somehow think I messed things up. With both the 1st and 2nd order circuits, the voltage dropped far sooner that the 310Hz target. I guess I was expecting something north of 8.5V at 310Hz the appropriate logarithmic drops for each circuit.
Can anyone give me some guidance here? What am I doing wrong? Be nice Like I said, I am just starting to explore the analogue world. I was also going to try and simulate this in LT Spice but have not got that far...
Thanks,
Mark
-----------------------------------
Here is a representation of the circuit:
9 VAC -------R-------------------R---------------- OUTPUT
| |
C C
| |
GD GD
-----------------------------------
Here is the recorded data:
Exp 1Exp 2
R=513.2,510.8R=513.2
C=1u,1uC=1u
f=310Hf=310H
fV with 2nd order circuitV with 1st order circuit
309.099.24
608.49.1
1205.88.6
2402.97.05
3102.76.42
4801.74.8
9600.5442.8
20000.1821.44
40000.0440.709
80000.0090.306
Software guy here who has developed an interest in hardware. I started with a RPI then an Arduino. Now I am starting working with basic discreet circuits and going analogue! Mind bending stuff. Not the precise 1's and 0's I am used to working with.
I am trying to get my arms around low and high pass filters with RC components. I have both a signal generator and new Rigol DS1054Z oscilloscope to help me through my learning curve.
To start, I built a circuit targeted at blocking signals above 310Hz using a 510Ohm resistor and a 1uF capacitor (electrolytic) . I built a first order and second order version of the circuit (see below) and then ran tests on the oscilloscope measuring the amplitude in V at different frequencies from 30 to 8K Hz. The results from the tests are below.
I somehow think I messed things up. With both the 1st and 2nd order circuits, the voltage dropped far sooner that the 310Hz target. I guess I was expecting something north of 8.5V at 310Hz the appropriate logarithmic drops for each circuit.
Can anyone give me some guidance here? What am I doing wrong? Be nice Like I said, I am just starting to explore the analogue world. I was also going to try and simulate this in LT Spice but have not got that far...
Thanks,
Mark
-----------------------------------
Here is a representation of the circuit:
9 VAC -------R-------------------R---------------- OUTPUT
| |
C C
| |
GD GD
-----------------------------------
Here is the recorded data:
Exp 1Exp 2
R=513.2,510.8R=513.2
C=1u,1uC=1u
f=310Hf=310H
fV with 2nd order circuitV with 1st order circuit
309.099.24
608.49.1
1205.88.6
2402.97.05
3102.76.42
4801.74.8
9600.5442.8
20000.1821.44
40000.0440.709
80000.0090.306