- Joined Aug 24, 2008
What constitutes an RF choke? I mean, the impedance of an inductor at HF may constitute a choke at UHF. Is there a guideline?
Hi rjenkins. I'm actually aware of that. As I said above, I'm not really asking what an rf choke does, but rather a quantity of impedance such that an inductor can be considered a choke at some specific frequency.It's as much the specific application as anything.
Thanks, but as I said above, I'm aware of all of this. I'm looking for some designer's rule of thumb for determining an effective impedance that will satisfy the requirements of a given choke.Consider a coupling capacitor vs. a filter/smoothing capacitor - identical 0.1uF caps could be used for both applications, depending where they are in the circuit.
A choke tends to be an inductor used for blocking or isolating high frequency signals (or noise), often in power connections.
It could also be an inductive element in a power supply smoothing setup, like a PI-network C-L-C filter.
Think of choke point or choke hold; a choke is an inductor used to control / limit / regulate rather than as a resonant element.
Now that's interesting. I haven't run into the need for such a choke as yet, but I'm sure to in the future. Thanks.Chokes for high-frequency blocking or noise filtering may also be deliberately low-Q, using lossy core material or wound over lowish value resistors, to prevent any unwanted resonances affecting the operation of the rest of the circuit.
I realise there are multiple sources of attenuation between the output signal and the input of a multistage amplifier. The signal at the collector would attenuate across the collector resistor, then the choke, and then any decoupling capacitors between the power line and ground. Then it would be attenuated as it took a path to the input amp.In that example, the top of the collector resistor would also have a decoupling cap to ground as well as the inductor. Just the cap will give considerable attenuation.
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