atari punk color organ

[MrDEB]

curious if this has ever been done or even possible.
Am playing around building an Atari Punk Console but thinking of adding LEDs that are controlled by 3 band pass filters (low, mid high)
this is for another project for grandson to drive his parents nut with the sound and amuse him with the LEDs.

 

[MrDEB]

REVISING THE COLOR ORGAN. Using A SIMPLIFIED CIRCUIT THAT DOES NOT USE THE OP AMPS.
Original design used 2n3904 transistors, but using a MOSFET instead will conserve battery power a little
attached both designs

 

[Nigel Goodwin]

I don't see why you imagine the FET version would conserve any battery power?, at a quick glance it doesn't look like it would even work, with the FET's looking to be permanently biased ON?.

Both are utterly crap circuits anyway, and performance would be poor.

 

[MrDEB]

here is a video of the circuit with 2n3904 transistors.
My understanding and simulation using easyeda the PNP transistor loses about 1.5 volts aprox. The MOSFET way less.

 

[tumbleweed]

Original design used 2n3904 transistors, but using a MOSFET instead

Be careful. The original design uses a 2N3904 + 2N3906 transistors (the schematic shows the wrong symbol for the first transistor).

You can't just replace the 2N390x with a fet. Build the circuit as originally shown if that's what you want.

 

[Nigel Goodwin]

here is a video of the circuit with 2n3904 transistors.
My understanding and simulation using easyeda the PNP transistor loses about 1.5 volts aprox. The MOSFET way less.

Your understanding appears to be misplaced - 'if' the transistors are turned fully ON, then they will only lose a couple of hundred millivolts, but this poor circuit is unlikely to achieve that. I don't see how the FET circuit will improve on that?, it depends on how well they are driven - but the circuit you posted appears to have them permanently biased ON anyway?.

In any case it doesn't matter if you lose a little voltage across the transistors or FET's as LED's are current driven - you've already got series resistors to lose voltage and lower the current, the drop in the transistors/FET's is only going to add a little to that.

As others have said, you can't just repace transistors with FET's, and there seems no advantage anyway.

 

[MrDEB]

after making the changes as suggested I think I can make my grandson a kool toy

 

[Nigel Goodwin]

Well we're back on random circuit changes that will entirely stop it working

As you were told the FIRST transistor was drawn with the wrong polarlty, why did you leave that one wrong and change the other three?.

 

[MrDEB]

will check thanks
found my mistake, I had the 2n3906's upside down

 

[MrDEB]

well I assembled the Jamco color organ kit but want to use MOSFETs to control up to 5 amps per channel (3 channels) but not real sure. plan to use IRF 520 N CHANNEL MOSFETS.
have attached the schematic for the assembled color organ kit

 

[MrDEB]

here is what I came up with. Have not planned to install LEDs

 

[rjenkinsgb]

That will not work as you hope, it's unlikely anything would ever give any output.

You need to use P-channel MOSFETs (or PNP transistors) driven from the collectors of the 2N3904s in the original circuit.

In other words, the higher power output stage replaces the LEDs in the original.

 

[MrDEB]

Perhaps just eliminate the transistor and just use the N channel MOSFET?
Going to connect a 555 timer on a breadboard and experiment using the MOSFET.

 

[rjenkinsgb]

Perhaps just eliminate the transistor and just use the N channel MOSFET?

No.

Or at least, not if you want it to actually work properly!

 

[MrDEB]

using the schematic in post #10, I need to control some LED rope lights with a maximum of 5A per channel.

 

[MrDEB]

here is something I found but why the led and 1K resistors?

IRF520 MOSFET Switch Module

IRF520 MOSFET Switch Module Description: MOSFET is an electronic devices with good switching characteristics. It is widely used in circuits, such as power supplies switching ,motor drives, lighting dimmer and so on. Relay is another kind of module with switching characteristics. Since

www.twinschip.com

 

[rjenkinsgb]

Indication that it's on, and to ensure the FET switches off properly.

See post #12. You cannot add N channel MOSFETs to the circuit without a lot more complexity.

 

[tumbleweed]

here is something I found...

And how in the world is that any different from your schematic that tried replacing the transistor with a MOSFET that you've been told WON'T WORK!.

As above. See post #12.

 

[MrDEB]

Here is the circuit I have been using with the IRF520 MOSFETS and it works as planned.

https://www.electro-tech-online.com/threads/computer-christmas-lights.163643/page-2#post-1425361

Same connections to the mosfet

 

[For The Popcorn]

And how in the world is that any different from your schematic that tried replacing the transistor with a MOSFET that you've been told WON'T WORK!.

As above. See post #12.

But it's on a circuit board, and it's RED! That makes ALL the difference!