building test gear?

[Neil Groves]

I just finished my fuction generator and i works ok i guess, the waveform looks like it is 'breathing' at certain frequencies, i looked online for abnormalities associated with the XR2206 and found ready made off the shelf equipment that does more and costs less than the simple circuit i built, then after more researching i found power supplies that would cost me less to buy than to build my own, so my question is why build ones own test gear if you can buy better stuff at a cheaper price? at first glance it looks a good deal to build your own stuff as components are cheap, but then you come to boxing it up and when you total up the cost of the enclosure, knobs etc you find you might as well have bought the damn thing off the shelf!

I suppose it's just nice to be able to say " i built this "?

Neil.

 

[Diver300]

In all electronic stuff, whether test gear or not, the cost comes from the development. It is only worth making things that are so specialised that no-one else has put one into production.

Sometimes there is equipment that does what I need, but it does so much else as well that it costs more than it would cost me to make one that only does what I want.

As you point out, boxes and knobs can add massively to the cost. If you don't mind a bare bit of veroboard it can be much cheaper.

 

[JimB]

I just finished my fuction generator and i works ok i guess, the waveform looks like it is 'breathing' at certain frequencies,

At an inspired guess, based on experience, these frequencies where the "breathing" happens will be multiples of the mains supply frequency, 60hz if you are in the USA.
The problem is due to slight amounts of stray signal at 60hz which is all around your work area. Normally this is too small to notice, but when the signal from your function generator is at 61, 121, 181hz, you can see the 1hz beat between the wanted signal and the mains and it harmonics.

i looked online .... and found ready made off the shelf equipment that does more and costs less than the simple circuit i built, .... so my question is why build ones own test gear if you can buy better stuff at a cheaper price?

A lot depends on the starting point, as well as the destination.
If you have to buy all new parts and the box to put it in, from a full price supplier, then the thing you build will usually be more expensive than the bought in item, especially if the bought item is from the lower end of the market.

However, if you have some old equipment (junk?) which partly does what you want, modify it
so that it will do exactly what you want. Now compare costs, you will have made a good saving.

I suppose it's just nice to be able to say " i built this "?

Yes it is, especially when you have made something useful out of a pile of junk.


As time goes by and you have been at the hobby for a number of years, you build up a supply of "stuff", especially if you are professionally associated with electronics as I am, (or should say was).
From that supply of stuff, if you have room to store it, over the years varous things which in themselves are just junk, can come together to make something useful.

Have a look at the attachments for an example.

JimB

 

[Neil Groves]

Thanks Jim....i recently threw out an old power supply from a computer after upgrading, thinking 'i'll never use that again'.....now i find i could have used it for a low current +/- power supply for playing with op-amps lol

i do that way too often in an attempt to not be a hoarder.

Neil.