Hello people.
I am trying to make this circuit.
https://www.electronicsforu.com/electronics-projects/simple-high-frequency-power-amplifier
I am interested in DC to 3Mhz max.
I am unsure about The RFC ferrite balun core. I have no idea about shape or size needed.
Can anyone help me?

David Miles

 

Find an old-school Cable-TV-"Splitter",
open it up, and the prize awaits You inside.
.
.
.

 

I am interested in DC to 3Mhz max.

This circuit will not work near DC. C1, C2, L1, RFC and C5 all block DC and low frequencies.
L1 & VC1 work best at one frequency.
This amplifier is built to work at one frequency, that is set by L1 & VC1.

 

The very old amplifier circuit was designed by students in South Asia.
It produces interference to other communications that makes it illegal.

 

It might take a pretty good purchasing agent to find a suitable air variable capacitor.

 

It might take a pretty good purchasing agent to find a suitable air variable capacitor.

There is a ton of NIB rf power LC stuff online. Not cheap but easily found. We use and repair lots of older industrial RF matches for plasma chambers.

 

This circuit was not "designed", but rather drawn based on what looks good. It might sort of function on ham radio frequencies, but not very well. It appears to be a single frequency application, and it is not suitable for any other applications. In addition, it is a "class C"amplifier and will deliver a rather distorted signal at any frequency except the one it is tuned to.

 

Why do You need "DC to 3Mhz" ???
How much Power do You need ??

You're not likely to get DC from any RF-Amplifier,
DC and RF just don't mix well.

For high-Power-Broadcasting, a single, huge, Vacuum-Tube may be the simplest solution.

Just purchase a Linear-Booster-Amplifier for CB-Radio.
All the inevitable Bugs have already been worked-out.
It will go all the way to ~30Mhz comfortably, and without any drama.

Solid-State-RF-Amplifiers work by special "Magical-Spells",
it's almost impossible to make one operate the way it's supposed to on paper.
Fudge-Factors seem to apply to every single part,
including what time of the Day it was manufactured.
.
.
.

 

Industrial Solid-State-RF-Amplifiers work just fine for decades 24/7 because they are designed properly on paper instead of copied from some random internet site.
https://www.trumpf.com/en_US/products/powerelectronics/plasma-excitation/truplasma-rf-series-3000/

https://www.trumpf.com/en_US/products/powerelectronics/

 

Thanks for all your answers- really good.
As I need something tunable, I will now obviously drop the design I posted.
I will buy something if I have to, but I would prefer to make something myself if I can.
So, can anyone point me to a circuit design that could be tunable from say 1Khz to 3Mhz with a reasonably clean output signal? It doesn't need to be super powerful.

David

 

I'm sorry everyone, I didn't mean tunable, I meant something with a suitable bandwidth!

David.

 

How much gain and how much power? There are opamps that can operate at 3MHz.

 

How much gain and how much power? There are opamps that can operate at 3MHz.

Hello. I would like to have a circuit that can light up a 10watt led module, or a bunch of normal white leds.

 

LEDs use DC current. The output of an RF amplifier is AC current.
You can connect LEDs back-to-back plus a current-limiting resistor then some LEDs light during the positive voltage swing and the other LEDs light during the negative voltage swing.
Why use audio, ultrasound and Radio Frequencies to light LEDs??

 

Hello. I would like to have a circuit that can light up a 10watt led module, or a bunch of normal white leds.

Are you talking about wireless power transmission? That is an entirely different story. You do not need an RF power amp for that.

 

I would like to have a circuit that can light up a 10watt led module, or a bunch of normal white leds.

Please tell us what 10W LEDs you want to use. What power you have. We are looking at a LED driver.
Also, I don't know of a reason to turn a LED on/off at 3mhz. Maybe a laser LED.

 

I think he wants to use RF power to light the LEDs wirelessly.

 

I think he wants to use RF power to light the LEDs wirelessly.

Where do people come up with the curious notions that they do?

 

Bandwidth in that range is easy to get. The key questions are what kind of power you need and what the source and load impedance are.

 

Bandwidth in that range is easy to get. The key questions are what kind of power you need and what the source and load impedance are.

Funny you should mention that. One recent poster claimed, without offering any evidence, that they were negligible. What he meant was that he did not know how to measure, compute, or estimate them, so they were going to be ignored.