Mine doesn't have one, just the arbitrary voltage control knob. How difficult would it be to add one to monitor current and voltage?

since a variac is mostly used to bring a radio up slow, the current draw is more a concern than accurate voltage.
An Amp meter could be added externally from the AC output of the variac, and a female AC socket of the other end. You can monitor the voltage if you want to with any DVM or VTVM.

:since a variac is mostly used to bring a radio up slow, the current draw is more a concern than accurate voltage.
:An Amp meter could be added externally from the AC output of the variac, and a female AC socket of the other end. You can monitor the voltage if you want to with any DVM or VTVM.
:
I agree with Warren. I have an isolation transformer pluged in the wall then the Variac pluged into the isolation transformer then the unit pluged into the output of the iso trans. I use a DVM to measure voltage as i operate the Variac. I also use a small Amp clamp current meter to measure the current draw as voltage increases. With this setup i have not been shocked by a chassis and know when to stop increasing voltage and start looking for the high current problem.
Mitch

::since a variac is mostly used to bring a radio up slow, the current draw is more a concern than accurate voltage.
::An Amp meter could be added externally from the AC output of the variac, and a female AC socket of the other end. You can monitor the voltage if you want to with any DVM or VTVM.
::
:I agree with Warren. I have an isolation transformer pluged in the wall then the Variac pluged into the isolation transformer then the unit pluged into the output of the iso trans. I use a DVM to measure voltage as i operate the Variac. I also use a small Amp clamp current meter to measure the current draw as voltage increases. With this setup i have not been shocked by a chassis and know when to stop increasing voltage and start looking for the high current problem.
:Mitch
:
I suggest a standard analog panel meter for current. The round AC current meters are plentiful; they are about 3 1/2 inches round. 3 amps is fine. Analog meters are good because you can see when the current is fluctuating, like when a component or transformer is failing, or the current suddenly starts rising. It's best to fuse it also. I always have an isolation transformer in front of my variac.
Johnnysan-

:::since a variac is mostly used to bring a radio up slow, the current draw is more a concern than accurate voltage.
:::An Amp meter could be added externally from the AC output of the variac, and a female AC socket of the other end. You can monitor the voltage if you want to with any DVM or VTVM.
:::
::I agree with Warren. I have an isolation transformer pluged in the wall then the Variac pluged into the isolation transformer then the unit pluged into the output of the iso trans. I use a DVM to measure voltage as i operate the Variac. I also use a small Amp clamp current meter to measure the current draw as voltage increases. With this setup i have not been shocked by a chassis and know when to stop increasing voltage and start looking for the high current problem.
::Mitch
::
:
:
:I suggest a standard analog panel meter for current. The round AC current meters are plentiful; they are about 3 1/2 inches round. 3 amps is fine. Analog meters are good because you can see when the current is fluctuating, like when a component or transformer is failing, or the current suddenly starts rising. It's best to fuse it also. I always have an isolation transformer in front of my variac.
:Johnnysan-
:
:
:
:

::::since a variac is mostly used to bring a radio up slow, the current draw is more a concern than accurate voltage.
::::An Amp meter could be added externally from the AC output of the variac, and a female AC socket of the other end. You can monitor the voltage if you want to with any DVM or VTVM.

Most VARIACs have two ways to connect them, one being zero to one hundred per cent of the rotation of the slider, the other will give you zero to 135 per cent. On mine, I have an AC meter that will show the actual Voltage (a meter I bought in 1955 at an army surplus store for fifty cents) My line Voltage runs about 118 Volts, so I can vary the Voltage from zero to 135 percent of that. You can figger the math, my coffee hasn't kicked in yet. I tried to explain to my wife that a VARIAC puts out a pure sine wave, whereas a cheap lamp dimmer distorts the wave and cannot be used on reactive loads. Try explaning the Sahara desert to an Eskimo.
Lewis

::::
:::I agree with Warren. I have an isolation transformer pluged in the wall then the Variac pluged into the isolation transformer then the unit pluged into the output of the iso trans. I use a DVM to measure voltage as i operate the Variac. I also use a small Amp clamp current meter to measure the current draw as voltage increases. With this setup i have not been shocked by a chassis and know when to stop increasing voltage and start looking for the high current problem.
:::Mitch
:::
::
::
::I suggest a standard analog panel meter for current. The round AC current meters are plentiful; they are about 3 1/2 inches round. 3 amps is fine. Analog meters are good because you can see when the current is fluctuating, like when a component or transformer is failing, or the current suddenly starts rising. It's best to fuse it also. I always have an isolation transformer in front of my variac.
::Johnnysan-
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