Breadboards - How bad are they at RF?

[Mikebits]

Hi.

I do agree that it is a nice article and a good test. However I noticed that the resistors and capacitors on the breadboard looks to be put together in a hurry. All the component legs have huge bends as well as the legs way longer than they need to be.

I bet if you've used some time and had only sharp bends on the component legs, then it would solve some of the problems.
Therefore I thing the breadboard cannot be that guilty

My young Padawan, actually sharp bends will add additional problems with mutual coupling, both inductive and capacitive. Skyscraper circuits have been used in RF for decades.

 

[Dean Huster]

It has often been said by the sages of analog design that it is far easier to make a circuit oscillate than it is to make it amplify properly.

 

[Mikebits]

It has often been said by the sages of analog design that it is far easier to make a circuit oscillate than it is to make it amplify properly.

So true, so true.

 

[audioguru]

It has often been said by the sages of analog design that it is far easier to make a circuit oscillate than it is to make it amplify properly.

When I was young and played with chemicals, all my rockets exploded and all my bombs flew up very high.
Later when I played with electronics my first amplifier oscillated.

 

[atferrari]

When I was young and played with chemicals, all my rockets exploded and all my bombs flew up very high.
Later when I played with electronics my first amplifier oscillated.

Pure Murphy in action, AG!

 

[4pyros]

Over the years many threads have revolved around the poor operation of a circuit built on a breadboard, the type with lots of strips where components can be plugged in to make the connections.

I never thought breadboards were invented for RF circuits, just digital ones.

 

[Sceadwian]

Breadboards weren't so much invented as they just happened. Far before what most people would call a breadboard existed Amateurs would use scrap wood (sometimes an actual cutting board) pegged with nails to put radio's together using solder. The modern version has a patent associated with it from 1971 (referenced from a maker (BPS) as to the origins of the solderless breadboard) (US Patent #203938) but I can't look up the patent on the governments site to verify.

 

[Mikebits]

Breadboards weren't so much invented as they just happened. Far before what most people would call a breadboard existed Amateurs would use scrap wood (sometimes an actual cutting board) pegged with nails to put radio's together using solder. The modern version has a patent associated with it from 1971 (referenced from a maker (BPS) as to the origins of the solderless breadboard) (US Patent #203938) but I can't look up the patent on the governments site to verify.

Lol, only you would know this, your a plethora of knowledge. Our forum Cliff Claven

 

[dr pepper]

I have a very oold prototyping board which is just this, hardboard (presspan) with holes in and shortened nails with rubber sleeves, you put the pin through the board then put 2 or more comoent wires against the pin then hold them in place with the rubber sleeve.
Never used it too much messing about, it would probably be a lot better at rf than a wishboard though.

 

[Sceadwian]

Lol, only you would know this, your a plethora of knowledge. Our forum Cliff Claven

I have a favorite quote Mike that I got on a T-shirt from my wife for Christmas a couple years ago. It says "I really do know everything, I just can't remember it all at once"

That however is what the Internet is for!

 

[JimB]

A few days ago Grossel commented:

I do agree that it is a nice article and a good test. However I noticed that the resistors and capacitors on the breadboard looks to be put together in a hurry. All the component legs have huge bends as well as the legs way longer than they need to be.

I bet if you've used some time and had only sharp bends on the component legs, then it would solve some of the problems.
Therefore I thing the breadboard cannot be that guilty

So, in the interests of being thorough I recreated the circuit on the same breadboard as shown in the attached picture.

In all fairness I must admit that it did make a difference!

When the 2N3904 was in circuit, it oscillated at about 83kHz. (Was 200kHz in the previous test).

When the BFY90 was in circuit, it oscillated at 850MHz. (Was 700MHz in the previous test).

So, as they say in all the best court room dramas on TV:

"Appeal denied! Take him down!"

JimB

 

[audioguru]

Some component wires on your new neat circuit are still far too long. Each long wire is an inductance that messes up high frequencies.
The wires with the alligator clips are also inductances.

 

[Sceadwian]

RF components are best off done 'dead bug' style. You can use anchor points to a common breadboard with plastic pins.