Too much base ?

[saturated]

I wanted to set up a circuit and see what happens.

Previously I was trying to do something different and after gathering a few components my calculations showed a voltage drop across the collector resistor of 23.9 when Vcc was 24 volts 

So today I wanted to put together a circuit with a lower base resistor and see 🙈 if it would melt or blow up the transistor I had no idea what it would do.

Here is the schematic

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So I put it together and dialed up the voltage and kept watching for smoke but really nothing bad happened (I don't think) 

Also I measured emitter current

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And here are my results

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One thing I am noticing is the lower beta value seems iirc in all the book experiments i did beta was about 170 

Seems like the base emitter voltage drop looks good so maybe I was nowhere near Chernobyl territory idk and that wasn't what I was trying to do.  I tried to feel if the transistor was getting warm/hot but it's tiny and I couldn't really tell.

My main interest was with the suspected huge voltage drop across the collector how much was gonna be left for the emitter resistor 

[J M Fahey]

The classic "universal" values for these ultra simple gain stages is:

3k3 to 4k7 load resistor with 1M Base>Collector.  NOT Base>+V as you show.
or
10k load resistor with 3M3 Base>Collector.

The beauty is that it is self-adjusting so it works with almost any transistor, no need for careful selection or trimming.

Try it and post results.

You will see Collector self biases *near* V/2 which is what we want.

Back in the day (in the 80s) I designed and published a series of Magazine articles showing how to DIY a ton of projects, from a single transistor Guitar booster to 6-12 channel mixers.

Many still in use today, 40 years later!!!!

[galaxiex]

Hey JM are any of those articles/projects around anywhere online? 

[J M Fahey]

No Internet in the 80s for the average Joe but now and then some devoted reader scans and uploads one.
I do have a few in some OLD hard disks, pulled from dead computers.

Not promising anything but IF I find one, or two, I´ll post them here.

[J M Fahey]

This is one from the series, easy to find because of, you know, "TOOBZ"  , but there are many others, mostly SS.

When I was a kid , "everybody and his brother" had a basic record player, WINCO brand, so pawnshops and old attics are choke full of them, everywhere.
So I published how to turn one of them into a Guitar amp.

This is the modded schematic:

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It has *one* error, easy to solve.

To save space, one PCB track goes through EL84/6BQ5 pin 1.

According to datasheet, there is nothing there, and pin is labelled NC, meaning "not connected" .... but on *some* tube brands, they use that "spare" pin to mechanically support things inside the tube.

That support wire grounds signal and mutes tube 

Mind you, only on *some* brands.

Solution is to, after drilling PCB, using a 5-6-7 mm drill to gently "shave" some copper around the 1 mm socket leg hole so track "ring" copper foil does not touch socket pin.

Veroboards do the same to cleanly cut tracks where needed.

Of course, you can also build it PTP.

Hundreds were made , used in recordings, etc.

This is the El Musiquero magazine, today at the cult/collectible status:

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