can you have a look at my eagle board layout - the Guru's mic amp

[audioguru]

Why do you need a relay?
Why use a reed relay instead of an ordinary relay?
Frequently a transistor can replace a relay unless the switched load is powered from a high AC mains voltage.

 

[danrogers]

I was just brainstorming ideas, I thought maybe a reed relay would take less power to operate than a standard relay, although im probably completely wrong.

The load will not be high voltage or ac, just low voltage logic from what i understand.

I really wish I understood electronics a bit more, but from my lack of knowledge is there a transistor that i can connect one leg to the output of the op amp, and the other two legs to be in a normally open state with each other, and close when a certain level of power is put into it from the op amp?

which family of transistor would I be best with?

 

[audioguru]

I was just brainstorming ideas, I thought maybe a reed relay would take less power to operate than a standard relay, although im probably completely wrong.

The load will not be high voltage or ac, just low voltage logic from what i understand.

Then you need a transistor, not a relay.
A relay is mechanical so it wastes a lot of power.

is there a transistor that i can connect one leg to the output of the op amp, and the other two legs to be in a normally open state with each other, and close when a certain level of power is put into it from the op amp?

Your explanation does not make sense. The output of an opamp can turn on a transistor or a Mosfet that can short two wires together if you want.
What do you want to switch on and off? How much power, how much voltage and how much current do they use when they are turned on?

which family of transistor would I be best with?

I cannot answer unless you provide the details to my questions.

 

[danrogers]

Ok thanks!

What I want to switch is an input to a encoder IC. The switches momentarily make to vcc, which is 5v at about 100ma.
I dont know what the draw would be once the connection is made to the IC, is there a way to find out?

The application you stated is (as far as i know) what I will need to do to short the switch and activate the input.

The thing Im majorly unsure on at the moment is what type of transistor, PNP, NPN, DJT etc etc?

PS. when this is working, let me know where to send you a crate of beer

 

[audioguru]

Ok thanks!

What I want to switch is an input to a encoder IC. The switches momentarily make to vcc, which is 5V at about 100ma.
I dont know what the draw would be once the connection is made to the IC, is there a way to find out?

It is said on the datasheet for the encoder IC. Which IC?

The application you stated is (as far as i know) what I will need to do to short the switch and activate the input.

A Cmos analog gate IC can switch the audio output from an opamp to somewhere else. Typical analog gates are the CD4066 quad switch IC, the CD4051 1 to 8 or 8 to 1 switch IC, the CD4052 dual 1 to 4 or 4 to 1 switch IC or the 4053 triple 1 to 2 or 2 to 1 switch IC.

The thing Im majorly unsure on at the moment is what type of transistor, PNP, NPN, DJT etc etc?

If you are switching audio then these ICs switch it and transistors are not needed.

PS. when this is working, let me know where to send you a crate of beer

I have never seen a crate of beer. Is it more than 24 bottles? I would like 96 bottles.

I have never seen an encoder that has audio inputs. Which encoder is yours?

 

[danrogers]

could you also explain what the following do emitter, a base, and a collector

would i connect the op amp circuit to the base, and the vcc to the collecter, then the emitter to the encoder ic?

 

[danrogers]

**broken link removed**

its a RF600E. they are not audio inputs they are just 5v logic i think. I just want to use the audio level to trigger one of the four inputs.



over here a crate is 24 but im sure i could find 96 spare ones somewhere lol

 

[audioguru]

Your wiring of a transistor is one that is not switched. It simply duplicates the audio from the opamp if it has a load resistor. Like a piece of wire.
A transistor is explained all over the web.

You forgot to say what is the encoder IC that you are switching audio from an opamp. What is the part number of the encoder IC?
What is the encoder IC supposed to do when it receives audio?

 

[audioguru]

**broken link removed**

its a RF600E. they are not audio inputs they are just 5v logic i think. I just want to use the audio level to trigger one of the four inputs.

Sorry i didn't see your reply at almost the same time as mine.
I think the encoder takes parallel data that turns on a radio transmitter when the associated decoder has "learned" its codes. Continuing data is converted into serial data at the decoder. Your preamp output is audio, not data so the encoder will not know what to do. Maybe if the audio is rectified and filtered then the encoder will turn on but you do not have any data to transmit.

over here a crate is 24 but im sure i could find 96 spare ones somewhere lol

Can you send me a big keg of beer like bars use? It holds hundreds of bottles of beer. Burp!

 

[Boncuk]

Hi Dan,

taking a glance of your PCB layout I have the impression you must be immensely rich.

Lots of wasted space! PCB manufacturers normally charge according to board size.

Here is a PCB design according to audioguru's schematic.

It's dimensions are 34X39mm (1.34X1.53inches)

You can reduce size further omitting the ground fill which I do not recommend. AF-amplifiers have the tendency to become radio transmitters.

Boncuk

 

[danrogers]

I did that doube reply thing without refreshing the page so it was my fault!

Right i see, so I guess i will have to try and recify the signal from the amp then and use that to switch my input somehow.

And yes, I will wait outside some pub's and see if I can 'borrow' some kegs


Hi Bon, thanks for posting that up. I wish I was rich haha, but that layout i posted was only a rough one just to make the wiring visable at these early stages

 

[danrogers]

Bon, have you used film caps for the low values and electrolytic for the higher values?

 

[audioguru]

Thanks for the pcb design, Boncuk.
Is your name Hans?

 

[Boncuk]

Thanks for the pcb design, Boncuk.
Is your name Hans?

Of course it is! In another forum I'm "Herman the German". You're there as well.

Everybody in our age group knows me well being "Hans". You should know, too!

No propaganda! That forum is bound to die!

Kind regards

Boncuk (Hans)

 

[Boncuk]

Hi Bon, thanks for posting that up. I wish I was rich haha, but that layout i posted was only a rough one just to make the wiring visable at these early stages

Must have been very early stages! (about 100 years ago).

Nobody will object if you try to make a PCB design with least space requirements.

My design was finished within 15 minutes. Trying to squeeze things a bit more I could reduce the board size by 0.2inches on two sides - still having a full ground fill and space for the mounting holes.

Regards

Boncuk

 

[danrogers]

lol well thats about the second pcb I've ever designed and the first being a simple led array

Hmmmm how am I going to rectify this amp output to slip this switch then i wonder ;/

 

[Boncuk]

Bon, have you used film caps for the low values and electrolytic for the higher values?

How should I know what kind of caps I'm using?

However I guess they are metallized polyester caps, low inductance, excellent for use as decoupling caps, better than any ceramic type cap.

They are WIMA MKS types, and good enough for almost every application.

Regards

Boncuk

 

[danrogers]

How should I know what kind of caps I'm using?

lol I was just looking at the different footprints. On my rough design I think I just used all the same package caps

 

[danrogers]

another question, how do I know which caps are polarized/ non-polarized?

for example, **broken link removed**

 

[Boncuk]

lol well thats about the second pcb I've ever designed and the first being a simple led array

Hmmmm how am I going to rectify this amp output to slip this switch then i wonder ;/

Hi Dan,

rectification is commonly done using a diode (or two, sometimes four in a full bridge rectifier).

To hold the rectified voltage for the time you intend use an electrolytic cap with the appropriate capacitance.

After this rectifier - smoothing cirucit connect an NPN-transistor to switch a load (relay) or use a MosFet to switch the load directly.

Take care to switch off the transistor by discharging the cap with a suitable resistor if there is no more triggering signal present.

Boncuk