New Voltage stabilizer for a TR4A - which to use?

[Lebro]

Yep, should be 10V

Bob

[Charlie D]

On 2/15/2022 at 8:46 PM, RobH said:

it is easy to build one into an old casing:

Rob:
I didn’t bother with the capacitors. I seem to remember (I think...) that the data sheet said that if the input and output leads were short, you did not need them. I’ve done 2000 miles with no problem, but wonder what your view is on the matter.

ALSO…
I rebuilt my regulator by putting the 7810 in the original regulator metal container and had all sorts of problems at first. The external connections are riveted through the insulated part to the inside connections. What happened, I guess due to age, was that there was a not so perfect electrical connection between the external connection and the rivet, resulting in intermittent operation of the regulator.

Nothing to be seen from the outside but I guess there was a film of corrosion between the rivet and external spade.

In the end I removed the rivet and made the through connection with a brass screw. All worked well after that.

To anyone thinking of doing this, check the resistance from the outside to the inside. It may save you a lot of head scratching.

Charlie.

Edited February 19, 2022 by Charlie D

[RobH]

Yes the capacitors are not strictly necessary in all cases as you say Charlie. The designer includes them for stability since long leads are inductive and might cause oscillation but they don't define what 'long' means. In terms of normal circuit boards it probably means more than few inches.  In any case, when powering car instruments a bit of high frequency oscillation on top of the DC wouldn't even be noticed.  

 I would include the capacitors because a car is a very electrically-noisy environment - those ignition spikes get everywhere and can be very large - so the capacitors reduce the possibility of over-voltage spikes damaging the chip.  

Since your regulator has survived for so long, that obviously isn't a problem on your car but it just might be for someone with a different setup and/or chip from a different manufacturer. 

 

[Lebro]

+1 for using capacitors

Bob

[Charlie D]

Rob,

Thank you for the explanation.

Over the years of reading both yours and Bob’s explanations of electronic things I have come to the conclusion that both of you have a

“Do it properly”  to  “Bodge it and run”

ratio better than 99:1

My problem is that I just love to bodge things.
There is such a great feeing of satisfaction when it works.
(Well… That’s my excuse…)

Charlie.

[stillp]

6 hours ago, Lebro said:

+1 for using capacitors

Bob

Same here.

Pete