How fast is a photoresistor when used in RF?
时间：04-05
整理：3721RD
点击：
Hello,
I am trying to build an RF attenuator for HF (1-30MHz).
My intention is to see how fast a photoresistor (LDR) is for this application.
I do not refer to the responce times of the LDR to the light intensity. I refer to the RF response of the LDR or otherwise the RF characteristics of the LDR for HF.
Would it be as good as a common resistor?
Take as an example the VTL5C1 vactrol
I am trying to build an RF attenuator for HF (1-30MHz).
My intention is to see how fast a photoresistor (LDR) is for this application.
I do not refer to the responce times of the LDR to the light intensity. I refer to the RF response of the LDR or otherwise the RF characteristics of the LDR for HF.
Would it be as good as a common resistor?
Take as an example the VTL5C1 vactrol
curious as to why you want to use this device ?
how much RF power were you planning to put through the LDR section ?
something like this is probably much better and it's likely to be impedance matched
http://www.hittite.com/products/index.html/category/250
Dave
Please review this paragraph from the PerkinElmer Vatrol databook:
You can calculate that the LDR capacitance reduces the achievable control dynamic with increasing frequency.
Thanks very much! That completely answers the question