When I first tried them the text box values weren't going anywhere, but now it looks like they work much better, but there are still some usability issues. The main problem is the fixed engineering units, such as uF for capacitor values. It is lame to type 10e-6 to search for 10pF. I also don't like typing values twice.
Here is how I like things to work:
I like the numeric entry fields to specify a single value or a range of values.
A single numeric value for a resistor's value, for example, could be 10K.
In this case I only want to see 10K resistors returned.
I don't want to be required to type 10e3 or 1e4 or 10000 (like an animal!)
For a capacitor I want to be able to type 10pF. This is an interesting value because 10e-12 does not have an exact standard IEEE floating-point representation. The database needs to have the correct floating-point fuzz in the query. Of course I also want to be able to type 10u or 10uF or 10UF for capacitance.
Ranges consist of two numbers, a minimum and maximum, similar to your sliders. They need to be in either two text boxes or in one text box with a delimiter. Using two text boxes with tab and shift-tab navigation back and forth between the boxes is okay.
To get the correct floating point representation, the best way is to subtract one floating point epsilon from the minimum value and add one floating point epsilon to the maximum value.
A single value can also be handled as a range where the minimum and maximum values are the same. Just please don't make me type the number twice!
Correctly handling units and numeric input on the web requires more code. I like test-driven development for this. I have found that it needs about two hundred of tests to get it right. Otherwise it breaks all the time, because fixing one problem causes others.
For example these should all return 10K 1e4 10e3 +1e4 +1e+4 1e1K 1e-6G 10.0K .01M 10000000m 10.000000000000000000000001K 9.99999999999999999999999999K 0.01M +0.01M +.01M 100000e-1
There is another issue which is the correct feedback to the user for entered numbers. In this case engineering units should be used, with a special case for capacitors to avoid nF and mF. By the time you are done it seems like a stupid amount of code but it is worth getting right.