Circuit Simulatioin

When its come to simulation, there's many things that i think how i should simulate the circuit. So, after keep asking Mr. Google, finally, its come to solution. The solution is i have to test the circuit 1 by 1. From the First circuit, the IR LED Current Stabilizer, Second circuit is Trans Impedance circuit and the last circuit is sallen key filter circuit. The result should be almost the same as theory result that i found in the article. Figure below shows the circuit and its result. I skipped the IR LED current stabilizer simulation, because i can't found LT1932 component, and plus, my supervisor assure the circuit will have no problem if the connection is right, because the circuit is original from the datasheet of the LT1932 which you guys can view here http://cds.linear.com/docs/en/datasheet/1932f.pdf.

Transimpedance Circuit 
Started with the trans impedance circuit simulation, you can see figure below:

Figure above shows the simulation circuit for trans impedance circuit. It is using Proteus for the simulation software. As can be seen it is 1.5V supply to the circuit and resulting 24.01mV. A transimpdance amplifier is an amplifier that converts current to voltage. Its input ideally has zero impedance, and the input signal is a current. Its output may have low impedance or in high-frequency applications, may be matched to a driven transmission line, the output signal is measured as a voltage. I assuming that the input voltage is 1.5V from the IR LED Current stabilizer and it is supposedly current. The noise gain for example the noninverting closed loop gain of this configuration determines the stability of the circuit. The reason for this is that any noise signal, no matter how small, can trigger an unstable circuit into oscillation. The DC gain is set solely by the resistors. The pole frequency is set by the feedback network, just as in the impedance function. Table below shows the current input and output for the transimpedance circuit.

Current Input (mA)	Voltage Output (V)
0.010	0.01
0.022	0.02
0.031	0.03
0.04	0.04
0.052	0.05
0.061	0.06
0.072	0.07

Sallen Key Low Pass FIlter
The second circuit is sallen key low pass filter. See figure below:

The circuit above is simulated using Multisim software. It is hard to simulate using Proteus, so i come with the solution by using Multisim. As can be seen, i'm not using OPA 2350 for the operational amplifier. Supposedly it is OPA 2350, but, i can't found it inside Multisim. As my supervisor advised, it is almost the same amplifier, as long as the result is there. So the function generator is set to 5V amplitude and the Frequency is set to 5Hz.
The sallen-key filter is a simple active filter based on utilizing op-amp stages, which is ideal for filtering analog frequencies. It is one of the most widely used filter topologies. One reason for its popularity is that this configuration shows the least dependence of filter performance of the performance on the performance of the op-amp. Another advantage of the configuration is that the ratio of the largest resistor value to the smallest resistor value and the ratio of largest capacitor value to the smallest capacitor value are low, which is good for manufacturability. A serious drawback is that the filter is not easily tuned. A low pass filter is a filter that passes low frequency signals but attenuates signal with frequencies higher that the cutoff frequency. Desire cut off frequency is 10 Hz which can be seen on the simulation, i get the 10 Hz cut off frequency.


As a summary, the both amplifier play important role to in very low frequency applications and it is commonly used in receivers for optical communications.

That's all by now.. Thank you.. Keep in touch..