[Heathkit] Off subject but sort of Heath - VI Curve Tracer

[Kenneth G. Gordon]

On 20 Feb 2007 Ralph Fischer W7HSG wrote:

> > Heath made an IT-2232 component checker.
> >
> > Some time about when Heath announced the checker, there was an
> > article (I know not where) for a similar device that used your own O
> > scope for the display. The checker had a power supply of some type
> > and the whole system produced a display very similar to the Heath.
> >
> > Does anybody out there in Heath Land know what I speak of and where
> > said schematic can be found?

One version is called "The Octopus". It is also know as a "VI Curve 
Tracer". You can see various versions via a link on this page:

http://octopus.freeyellow.com/octopus.html

The circuit has been around since about 1935.

I have built a very versatile version of this and use it regularly at work 
for checking components. Mine uses two Radio Shack low-voltage 
transformers with center-tapped secondaries, two rotary switches to 
choose various voltages and series resistors, and is line-powered.

It is especially useful, quick and accurate for checking diodes and 
transistors.

Some versions use an audio oscillator instead of 60 Hz voltages, and 
one could easily build a battery powered version using an NE-555 as 
the audio oscillator and a miniature audio transformer.

The voltage source must be AC in order for the circuit to work.

> > I have an IT 2232 but need a small unit to take to My son's QTH in
> > Montana when I visit there.

The really simple version of this can be built in a very small mini-box.

Ken Gordon W7EKB