# Discrete Transistor Design Work

1. ## Discrete Transistor Design Work

Hello everyone!

Below is an example of a circuit using discrete components that is heavy on transistors. I'd like to be able to do this type of design work and understand 100% how the circuit is functioning - but I am limping through the analysis.

I am looking for some advice on a starting point on how to learn this type of design work at a deeper level. I have an electrical engineering background but I am weak in this area of design. Maybe some books to recommend? Classes? Not sure exactly what category this falls under how how to research this more.

Thank you.

See attachment.

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2. ## Re: Discrete Transistor Design Work

Your schematic appears to be in a textbook. Does it have a step-by-step tutorial? Starting with the laser diode and its specs. Then adding the driving transistor and control clock. Then adding the photodiode with feedback (and explanation), etc.

Q1 & Q2 form a long-tail pair.
Q4 & Q5 look like a current source.

Link to website with a great many schematics for discrete components.

www.4qdtec.com

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3. ## Re: Discrete Transistor Design Work

Hello Brad thank you for the post to my message.

The text goes into a brief description of what the circuit can do but doesn't describe in detail. For example, the circuit can control the drive current, there is a current limit and a compensation for the loop , etc.

I want to be able to do this type of design work from scratch. The website is a good link for a reference but I need some more detailed material to study.

Any other ideas on how to grow my know of "discrete design with transistors" ?:)

Thanks.

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4. ## Re: Discrete Transistor Design Work

I would like to give you a good reference to understand discrete transistor design fundamentals. It's not complete but will give you a bright insight..
"Analogue IC Design: The Current-Mode Approach"-C.Toumazou,F.J.Lidgey,D.G.Haigh-1990
Don't get stuck-on its name "IC Design", the techniques are still same..

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5. ## Re: Discrete Transistor Design Work

Thanks for a push in the right direction! :)

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6. ## Re: Discrete Transistor Design Work

Transistors were featured in project books during the 1950's to the 1970's. (After the vacuum tube era and prior to the IC era.) Toss in magazine articles and the ARRL handbook. Articles explained how the circuits worked. These are tutorials for building with discrete components.

These techniques may come back into interest because a frequent power source was a 1.5v battery, and now we're seeing 1.8V become a popular standard.

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