Measuring AC Current

[Glowplug53]

Howdy,

I would like to measure current of an AC filament in a vacuum tube.
What type of meter would one use if a DMM was not available?

TIA

GP53

 

[John Fields]

On Wed, 6 Oct 2004 16:27:09 GMT, Glowplug53 <alanjc@nwlink.com> wrote:

Howdy,

I would like to measure current of an AC filament in a vacuum tube.
What type of meter would one use if a DMM was not available?

---
An AC ammeter.

--
John Fields

 

[CFoley1064]

Subject: Measuring AC Current
From: Glowplug53 alanjc@nwlink.com
Date: 10/6/2004 11:27 AM Central Daylight Time
Message-id: <41641CDD.D7456683@nwlink.com

Howdy,

I would like to measure current of an AC filament in a vacuum tube.
What type of meter would one use if a DMM was not available?

TIA

An analog AC current meter, a low-value series resistor with an AC voltmeter
across the resistor, a sensitive current transformer, or a fast hall effect
current sensor. If you're just doing a bench test, you also might want to
measure the current in the primary of the filament transformer and do the math
(generally transformers are over 90% efficient for loads between 20% and 80% of
rated load, so you can calculate VA in is close to VA out.

However, if the tube glows, you can be pretty sure the filament current is
within 20% of the manufacturers' spec.

http://www.drtube.com/tubedata.htm

Chris


Good luck
Chris