# Hitachi Oscilloscope V-212 testing question

#### Automan350

Joined Jun 15, 2015
45
Hi all, I have this oscilloscope on order. I plan to use it for work testing mini split and VRF inverter boards and car audio outputs.

I hear I will need a 1k resistor so the scope will read properly. Is this true? I ask because from my understanding the probes have a 10ohm resistor built in.
I am new to oscilloscopes, so any help setting it up for testing would help. I have a previous thread from thus site on this model oscope saved and will read it till I get comfortable.

#### KeithWalker

Joined Jul 10, 2017
2,517
The Hitache V-212 oscilloscope has a vertical amplifier input impedance of 1 Megohm in parallel with a capacitance of 23 pF. You can use a standard x1 or x10 oscilloscope probe with it.
If you don't have an operationl manual for it, I suggest that you download one on-line and read it before you use the scope.

#### Automan350

Joined Jun 15, 2015
45
The Hitache V-212 oscilloscope has a vertical amplifier input impedance of 1 Megohm in parallel with a capacitance of 23 pF. You can use a standard x1 or x10 oscilloscope probe with it.
If you don't have an operationl manual for it, I suggest that you download one on-line and read it before you use the scope.
I understand. What I do not understand is why I am told elsewhere to use a 1k resistor inline when setting amp input sensitivity and checking for clipping.

I have downloaded the manual. Honestly this forum has given me a better understanding then the manufacture manual.
Here is the link that has helped me get a solid understanding of my unit.

#### KeithWalker

Joined Jul 10, 2017
2,517
Putting a 1K resistor in series with the input to a 1M input impedance scope does not appear to make any sense at all. Can you give any more information on the source or reason for it?

#### Automan350

Joined Jun 15, 2015
45
My thoughts exactly. They said the reason was it provides a more accurate reading. I figured the guys here would advise different.

#### dl324

Joined Mar 30, 2015
15,097
I hear I will need a 1k resistor so the scope will read properly. Is this true?
Not likely. I don't know about your particular scope, but most have a high input impedance (unless you're working with 50 ohm equipment).

#### KeithWalker

Joined Jul 10, 2017
2,517
During my long and successful career, I specialized in electronic measurements. A shielded probe is usually used to make high impedance oscilloscope measurements. The cable and probe grounded shielding guard against picking up random EMI. Adding a resistor between the probe tip and the measurement point is introducing an unshielded conductor that will reduce the accuracy of the measurements and will be susceptible to picking up any radiated electrical interference.
I can not think of a single instance where I would recommend it.

#### Automan350

Joined Jun 15, 2015
45
Not likely. I don't know about your particular scope, but most have a high input impedance (unless you're working with 50 ohm equipment).
Thanks!
During my long and successful career, I specialized in electronic measurements. A shielded probe is usually used to make high impedance oscilloscope measurements. The cable and probe grounded shielding guard against picking up random EMI. Adding a resistor between the probe tip and the measurement point is introducing an unshielded conductor that will reduce the accuracy of the measurements and will be susceptible to picking up any radiated electrical interference.
I can not think of a single instance where I would recommend it.

I got word back from the guys on the audio forum. They say it provides a load on the outputs tested. One guy says it makes no sense as you do. The other says it presents a load on the rca and high level speaker outputs to simulate a load as designed.

I am no pro and figured why if a scope should be able to decipher as needed. Idk
I'm not installing any load resistors.

#### KeithWalker

Joined Jul 10, 2017
2,517
If it is used as a load, it should not be connected between the probe tip and measurement point, but from the measurement point to circuit common.

#### Automan350

Joined Jun 15, 2015
45
If it is used as a load, it should not be connected between the probe tip and measurement point, but from the measurement point to circuit common.
Ok so does that even make sense?

#### twohats

Joined Oct 28, 2015
322
I have read the same information 1k0 resistor on the end of the probe. (About 45 years ago).
I recall something to do with lowering the bandwidth, this was for servicing TV's.

#### Automan350

Joined Jun 15, 2015
45
I am glad I came to this site for you alls opinion and knowledge. I'm sure I'd be ok without them, but if anyone minds helping figure this out I'd appreciate it.

#### KeithWalker

Joined Jul 10, 2017
2,517
Ok so does that even make sense?
It all depends on the device you are analyzing and where in the circuit you are taking the measurements from. In most cases it will just mess up the accuracy of the measurement and introduce a bit of noise, but in some instances, it could damage the circuit you are working on. It sounds like a really stupid idea to me.

#### Automan350

Joined Jun 15, 2015
45
It all depends on the device you are analyzing and where in the circuit you are taking the measurements from. In most cases it will just mess up the accuracy of the measurement and introduce a bit of noise, but in some instances, it could damage the circuit you are working on. It sounds like a really stupid idea to me.
Yeah man I'll pass. I am not doing anything that needs a high level of accuracy.

I will likely pickup a spectrum analyzer next. I'd like to see what frequency range the rear channels of my radio sends out. Maybe I can verify crossover points.

#### tautech

Joined Oct 8, 2019
292
Yeah man I'll pass. I am not doing anything that needs a high level of accuracy.

I will likely pickup a spectrum analyzer next. I'd like to see what frequency range the rear channels of my radio sends out. Maybe I can verify crossover points.
All but a few SA have a min frequency of 9kHz whereas a modern DSO with FFT has no such limitation.
TBH a better and more modern scope than this Hitachi would be a better investment.

#### Automan350

Joined Jun 15, 2015
45
All but a few SA have a min frequency of 9kHz whereas a modern DSO with FFT has no such limitation.
TBH a better and more modern scope than this Hitachi would be a better investment.
I honestly have no clue what you are meaning to say besides SA being a spectrum analyzer.

Do you mind breaking the abbreviations down? I know you're saying a modern scope would be better as it has more features. It's my first scope and I figured this would be light years better then a $100 digital scope. I actually paid$70 for this one. More modern exceeds that unless you know of a site I can find them used cheap.

Either way if you know of any sites I can make my next purchase at please post regardless of pricing.

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#### MrChips

Joined Oct 2, 2009
27,111
All but a few SA have a min frequency of 9kHz whereas a modern DSO with FFT has no such limitation.
TBH a better and more modern scope than this Hitachi would be a better investment.
SA = spectrum analyzer
DSO = digital sampling oscilloscope
FFT = fast Fourier transform
TBH = to be honest

#### KeithWalker

Joined Jul 10, 2017
2,517
All but a few SA have a min frequency of 9kHz whereas a modern DSO with FFT has no such limitation.
TBH a better and more modern scope than this Hitachi would be a better investment.
The Hitache V-212 oscilloscope has a bandwidth of 20MHz and will be ideal for the TS application. A modern digital oscilloscope with FFT capability is a very expensive tool. I made my own audio spectrum analyser using a ATMega328 microcontroller with a 1.7" OLED color display.

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#### Automan350

Joined Jun 15, 2015
45
The Hitache V-212 oscilloscope has a bandwidth of 20MHz and will be ideal for the TS application. A modern digital oscilloscope with FFT capability is a very expensive tool. I made my own audio spectrum analyser using a ATMega328 microcontroller with a 1.7" OLED color display.
Do you by chance have a write-up on this?

I am very mech inclined and am a very hands on old school kinda guy. I'd really like to look at making one. The frequencies measured would be 30hz to 20k audio. 50vac will likely be the max voltage.

#### Automan350

Joined Jun 15, 2015
45
SA = spectrum analyzer
DSO = digital sampling oscilloscope
FFT = fast Fourier transform
TBH = to be honest
Thank you sir!