"Octopus" curve tracer: component choice question

[eti]

Is it important that the resistors in this circuit are 1/2 watt (except the 1 watt one)? I only have 1/4 watt - I know I can double up, but want to know if it is necessary? Thanks!

[bob91343]

Even if all the 6.3V were across the 560 Ohm resistor, the dissipation would be about 80 milliwatts so don't worry about it.  1/8 Watt resistors would even be okay.

[nali]

I think someone somewhere got their Ohm's Law calculations wrong for the 1K resistor too... it should be 1mW not 1W!

[eti]

I think someone somewhere got their Ohm's Law calculations wrong for the 1K resistor too... it should be 1mW not 1W!

  Hehe, thanks!

[eti]

Even if all the 6.3V were across the 560 Ohm resistor, the dissipation would be about 80 milliwatts so don't worry about it.  1/8 Watt resistors would even be okay.

Much obliged, thanks for taking the time to help. Happy 2022, when it arrives!

[eti]

So does one connect the outputs of the tracer directly to the scope, or to the probes of the scope leads?

[NiHaoMike]

I would say to use coax lines with BNC plugs attached, the signal level is pretty small. Also, instead of a transformer and voltage divider, how about a cheap microcontroller operating as a sine wave DDS with a RC filter to filter two opposing PWM outputs? Then it can be battery operated and variable frequency.

[eti]

I would say to use coax lines with BNC plugs attached, the signal level is pretty small. Also, instead of a transformer and voltage divider, how about a cheap microcontroller operating as a sine wave DDS with a RC filter to filter two opposing PWM outputs? Then it can be battery operated and variable frequency.

A good idea, I have a DDS module here, but the very purpose of this thing is to keep it simple for me, and keep my focus on fundamentals. Once we introduce  micros into it, we wander off down the side lane which is the insanity of software, and all that nonsense - I am trying to learn about component characteristics, not how to write C code or learn a new SDK 

Computers and digital garbage is already too much in our faces all the hours of the day, and I am already on the PC too much, and so this HAS to be analogue only, if for nothing else, than for the most crucial thing - MY SANITY 

I like to K.I.S.S. - thanks for the suggestions.

[eti]

works