background knowledge
Operational amplifiers (op amps) have strong versatility. Can be used for mathematical operations such as addition, subtraction, multiplication, integration and differentiation. Many electronic circuits use operational amplifiers as their components, such as amplifiers, filters, oscillators, and flip-flops. Operational amplifier OP is a commonly used component in signal processing and signal conversion. Commonly used are two types of non-inverting input and inverting input.
The non-inverting amplifier is another basic operational amplifier circuit that uses negative feedback to stabilize the total voltage gain. The negative feedback of this amplifier can also increase the input impedance and reduce the output impedance. For the non-inverting amplifier, since the feedback loop is to the negative phase end, its amplification factor has nothing to do with the input signal. Even if the internal resistance R of the input signal changes significantly, this change will not be introduced into the amplifier's amplification factor.
The inverting amplifier is affected by the internal resistance of the signal. However, non-inverting amplifiers also have certain inconveniences: if zero adjustment is performed on the inverting end of the non-inverting op amp or an addition circuit is added, the signal source impedance will change and the gain will change, which requires special attention. Generally, when a non-inverting amplifier is used, the inverting terminal does not introduce other circuits except for connecting the feedback circuit.
Today's problem
I want to know how to find the input impedance of a non-ideal non-inverting amplifier as shown in the figure below.
I have an equation here, but I don’t know how to find it:
Among them, A(s) is the s-domain gain of the operational amplifier (also non-ideal). Obviously, the impedance is approximated, so there must be an approximate value in the circuit that I have not seen. I know that Ricm>Rid, maybe R0 is similar to R1 or R2, but I am not sure about the rest. I hope you can give some ideas.
LED power supply, CCTV center power supply device, LCD display power supply.
We can meet your specific requirement of the products, like label design. The plug type is US/UK/AU/EU. The material of this product is PC+ABS. All condition of our product is 100% brand new. OEM and ODM are available in our company, and you deserve the best service. You can send more details of this product, so that we can offer best service to you!
Power Supply,5V Power Supply,12V Power Supply, 24V Power Supply
Shenzhen Waweis Technology Co., Ltd. , https://www.waweisasdapter.com