For example;
circuit A have 12 transistor
circuit B have 6 transistor

both circuit produce the same result. What is the disadvantage of having many transistor? Need a general answer.. hope someone can forward me some link that i can prove with mathematical equation.

 

hi,
It really depends upon the circuit and the types of transistor.

Do you have example circuits you could post.?

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Eric
"Good enough is Perfect"

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A general response - more parts is likely to result in more opportunities for error and greater difficulty in achieving high reliability. The "math" is likely related to reliability.

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stevez

 

As stevez said, the more parts there are the more likely there will be a failure, so the reliablity will be lower.

However, it could be that the simple solution produces a marginal design that does not work quite as well as the more complex solution.

JimB

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Experience is directly proportional to the value of the equipment ruined.

 

There is another twist to the fact that more parts lead to a greater chance for failure of a single part. If the additional parts are for redundancy, i.e. tolerance tolerance, then the chance that a part failure will result in loss of critical function can be reduced. John

 

jpanhalt touches on something that would be nice to convey to many who come here to this forum. Intuitively, simple is better but only to a point. Many people post here wanting a simple circuit but become frustrated when simple isn't getting the job done. A goal of good design would be the simplest circuit that addresses all of the issues.

A good example for beginners is possibly a look at 3 terminal adjustable voltage regulators like the LM317. Quite often the circuit depicted has a very few parts. A good review of the datasheet reveals additional parts and an explanation for their purpose. An example might be the addition of a diode to prevent a capacitor on the output from damaging the regulator.

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stevez

 

You can state your requirements in any of a number of ways, but there is no way to get to done, without doing this first.

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We never have time to do it right; but we always have time to do it over.

 

A schema would be handy.

Perhaps you mean that a circuits is driven via discrete darlington transistors, will double the amount of transisitors but lower the burdon on the driver stages, and improve the gain.

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There are more ways to get to Rome.

Electricity, Electric clocks, Meters and Trains are great.

 

An excellent audio amplifier has many transistors.
A very poor audio amplifier has only a few transistors.
The results are certainly not the same.

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Uncle $crooge

 

Transistorized Radio receivers of yesteryears used to contain this as AD & business gimmick... 6 transistor 4 band radio
Then IC packaging technology-- boast of their capability-- as years pass by, few thousand more will be adding for a unit area of the CHIP.

As rightly put, circuit optimization, speaks what minimum components one uses to get a known standard of performance-- and the stability depends on quality of design.

Many a times we enjoy critical analysis on circuits and their quality, and luckily how improve on them, from experts like Audioguru.

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Regards,
Sarma.

 

When I was 12 years old, my portable AM radio had 6 transistors.
My friend's radio was embossed on its cover, "14 Transistors".

We looked inside his 14 transistors radio and found one transistor was the detector diode and 7 transistors were connected in a circle but were not connected to the radio circuit!

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Uncle $crooge

 

I recollect, there was a radio design from Siemens in their technical literature books during 80s, entitled, "Radio with IC Maximum" In fact it had more than 12 to 13 Chips.

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Regards,
Sarma.

 

I will explain it with the very basic things. In general electronic, transistor circuit can be replaced by two port network. In general, transistor circuit can be replaced by "block system". I will tell you about two port network.

circuit A have 12 two port networks.
circuit A have 6 two ports networks.

Several things you should consider when considering two port network
Zin, Zout, Av, and frequency response. Higher Av is resulting lower Zin and lower frequency response. Higher Zin is better when dealing with low amplitude signal.

If the result truly same in amplitude, system response, and noise resistance, your design is amazing.

The disadvantages are just placement and bigger PCB.
Sometimes the cost is expensive.

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