using of any flash guns (Page 2): I doubt they use relay contacts. Thanks. My 260 has seen a lot use over time.

joer Loc: Colorado/Illinois

TriX wrote:

Personally, I would not risk it on my camera unless I could see the camera schematic. If there are really relay contacts, then I'd probably be OK, but if the camera uses a semiconductor device (like an SCR, Triac or some other PN junction device) to trigger the flash, I just wouldn't risk it. BTW, the 260 is a great meter - when I want to know if an AC circuit is really active before I work on it, I don't trust my DVM. I pull out the 260.

I doubt they use relay contacts. Thanks.

My 260 has seen a lot use over time.

Leitz Loc: Solms

joer wrote:

I apologize for hijacking the thread.

I don't think an apology is necessary, joer. This is good information, and pertinent to the OP.

BebuLamar

TriX wrote:

Fast enough for a constant voltage (I have a 260 also), but not nearly responsive enough to measure the peak. To measure accurately, you need a digital storage scope set to single shot mode, then you can see the entire waveform, both positive and negative peaks. Many modern DVMs have a max mode, but without knowing the response/settling time, you can't be sure of its accuracy for a pulse.

But would there be a peak? I think the trigger voltage is at its highest when the flash is ready. It only goes down as the flash fires.

BebuLamar

TriX wrote:

Personally, I would not risk it on my camera unless I could see the camera schematic. If there are really relay contacts, then I'd probably be OK, but if the camera uses a semiconductor device (like an SCR, Triac or some other PN junction device) to trigger the flash, I just wouldn't risk it. BTW, the 260 is a great meter - when I want to know if an AC circuit is really active before I work on it, I don't trust my DVM. I pull out the 260.

There is never be a relay contact as those are too slow. Old cameras simply have a couple of metal contacts mounted on the shutter curtain. I think new cameras use SCR at least among the Nikon. I saw situation when the camera would only fires 1 shot because the sync circuit continues to conduct until the trigger voltage from the flash is turned off.

TriX Loc: Raleigh, NC

BebuLamar wrote:

There is never be a relay contact as those are too slow. Old cameras simply have a couple of metal contacts mounted on the shutter curtain. I think new cameras use SCR at least among the Nikon. I saw situation when the camera would only fires 1 shot because the sync circuit continues to conduct until the trigger voltage from the flash is turned off.

I agree, and a relay would be too large as well. You're probably correct about the cap voltage at full charge being as high as it gets (assuming there's no inductance in the circuit to commutate the SCR or as a trigger transformer), but if it were my body, I'd want to see it on a scope - just being conservative as bodies are soooo expensive to repair (and it's one of the few electronic devices I own that I wouldn't be willing to disassemble). 😀

Cheers,
Chris

Apaflo Loc: Anchorage, Alaska

A Simpson 260 is a nice enough meter, but it is 100,000 Ohms per volt and you want 10 times that minimum.

Trust there are no relays involved either.

Bottom line is, don't connect a camera to it.

BebuLamar

Apaflo wrote:

A Simpson 260 is a nice enough meter, but it is 100,000 Ohms per volt and you want 10 times that minimum.

Trust there are no relays involved either.

Bottom line is, don't connect a camera to it.

The Simpson 260 has the specs of 20,000 Ohms per volt. But to measure 140V it should be set at least on the 250V scale and such it should have 5 megaohm input impedance.

Apaflo Loc: Anchorage, Alaska

BebuLamar wrote:

The Simpson 260 has the specs of 20,000 Ohms per volt. But to measure 140V it should be set at least on the 250V scale and such it should have 5 megaohm input impedance.

I had done a Google search, but I guess the 100K figure is with a HV probe, and 20K is the bare meter. (I haven't used a Simpson meter for decades! We shelved them when Fluke came out with their 8000A Digital bench meter in the mid-1970's.)

Regardless, 20K or 100K, it is not high enough! Likewise it is an averaging analog needle display, and that isn't always good enough either. As someone mentioned previously it really takes a digital storage oscilloscope.

With meters like the Simpson it is probably quite safe if the voltage reads fairly low. But anything with an average of 140 VDC is possibly getting peaks of at least twice that.

BebuLamar

Apaflo wrote:

I had done a Google search, but I guess the 100K f... (show quote)

20k/V is high enough because in the 250V range it's 5M impedance. Modern DMM's are typically 10M and oscillocope is 1M.

TriX Loc: Raleigh, NC

BebuLamar wrote:

20k/V is high enough because in the 250V range it's 5M impedance. Modern DMM's are typically 10M and oscillocope is 1M.

Yep, although the scope is typically used with a 10X probe, so 10 Meg also. I now typically use a DVM also (Fluke or Tektronix DM5010), but just can't bring myself to toss the old VOM.

Apaflo Loc: Anchorage, Alaska

BebuLamar wrote:

20k/V is high enough because in the 250V range it's 5M impedance. Modern DMM's are typically 10M and oscillocope is 1M.

Typically the scope is used with a 10x passive probe that adds a 9M series impedance, providing a 10M input impedance. That's twice your VOM, with either the DVM or the scope.

Apaflo Loc: Anchorage, Alaska

duplicate post

BebuLamar

TriX wrote:

Yep, although the scope is typically used with a 10X probe, so 10 Meg also. I now typically use a DVM also (Fluke or Tektronix DM5010), but just can't bring myself to toss the old VOM.

Simpson still sells the 260. It's something I would almost never use yet never toss out.

camerapapi Loc: Miami, Fl.

In my humble opinion the answer to your question is yes but, make sure the flash you buy is compatible with Nikon bodies.

mas24 Loc: Southern CA

k. v. rajasingham wrote:

Is it possible to use other flash units (don't know the trigger voltage) without any damage to my Nikon d7000

You must have one of those old flash units that you're not sure if it will zap or fry your camera, because of voltage. And you so much want to use it. Buy a current flash unit that is compatible to your camera, and you won't have to worry. You can get them as cheap as $50.. Yongnuo, Sunpak, Neewer, are just a few affordable ones. A friend had this same issue.