Author Topic: How to test this circuit pre installation  (Read 1693 times)

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Offline Chris Wilson

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How to test this circuit pre installation
« on: January 06, 2014, 11:36:39 am »
Any tips on a test set up for this simple circuit? Whilst I am confident it should just work I am curious as to how I might check it out before installing it in the amp cabinet.  It's a cathode bias circuit for a valve (tube) linear RF amplifier. Thanks.
« Last Edit: January 06, 2014, 12:22:28 pm by Chris Wilson »
Best regards,

                 Chris Wilson.
 

Lurch

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Re: How to test this circuit pre installation
« Reply #1 on: January 06, 2014, 11:40:08 am »
You know you can stick that screenshot in paint and trim all the black out (not racist) and save a lot of wasted bandwidth for anyone viewing it.
 

Offline Dave

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Re: How to test this circuit pre installation
« Reply #2 on: January 06, 2014, 11:51:26 am »
trim all the black out (not racist)
Hate to break it to you, but if you need to point it out... :D

How about building your circuit and testing it on a breadboard?
<fellbuendel> it's arduino, you're not supposed to know anything about what you're doing
<fellbuendel> if you knew, you wouldn't be using it
 

Offline Chris Wilson

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Re: How to test this circuit pre installation
« Reply #3 on: January 06, 2014, 12:13:46 pm »
I etched a pcb and built it this evening, just wondering what a bench test would entail, prior to testing it in the amp which has frightening HV levels and an expensive valve. Thanks.
Best regards,

                 Chris Wilson.
 

Offline Chris Wilson

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Re: How to test this circuit pre installation
« Reply #4 on: January 06, 2014, 12:25:27 pm »
You know you can stick that screenshot in paint and trim all the black out (not racist) and save a lot of wasted bandwidth for anyone viewing it.

I am hopeless with image manipulation. I have done some (none racial) manipulation for you :)
Best regards,

                 Chris Wilson.
 

Offline Andy Watson

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Re: How to test this circuit pre installation
« Reply #5 on: January 06, 2014, 12:41:42 pm »
Light bulb, or light bulbs - the (now frowned upon) tungsten type. Pull-up the datasheet for the TIP147 and workout its Safe Operating Area and hence the maximum current at 40V. Then you need a D.C. power supply of more that 40V and whatever light bulb as appropriate to limit the current.

I assume the TIP147 will be on a heatsink?

You might also want to look at how you label the adjustment pot. As it is it appears to be labelled for the voltage present across this circuit, however, when you put this circuit into your final thing (transmitter cathode bias cct I assume), the sense of the pot is going to have the opposite effect on the bias current.
 


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