British National Radio & Electronics School Course – Experiments

[Chris55000]

Hi!

For anyone who may be interested in re–creating their learning days or just out of curiosity, I will provide a list of items needed to carry out the "40 Analogue And Digital Experiments" described in the B.N.R.E.S. Advertisement:–

As well as the components needed below, you will also need:–

A) One 13A plug and 1.5m of three core mains lead, plus one piece of 5A terminal strip, four ways;
B) Two pieces of plain (non copper coated) 0.1" matrix board, 100 × 160 mm
C) One packet of double sided PCB terminal pins, 0.040" or similar size.
D) One reel of 26 swg tinned copper wire;
E) Sleeving – I suggest p.t.f.e. sleeving for durability;
F) Soldering–iron, Cored 60/40 solder and all the usual Electronics hand tools;
G) Two AA four cell battery holders and eight NiMH "AA" size rechargeable cells, plus charger to suit;

NB – use "three cell" battery holders if using dry battery supplies!

H) A selection of crocodile–clip leads
I) Multimeter and oscilloscope, if you don't still have the one supplied in the course, anything from a TQ "Servicescope" up will do!

Please note the Asian DSO Series "build it yourself scopes" may not always be ideal for this as some of the experiments involve very low frequency signals!

Components follow on in next posts!

Chris Williams

[Chris55000]

Hi!

Experiment 1:- Demonstration of the effects of applying DC to the Oscilloscope

a) Oscilloscope as described above;
b) Three AA cells and holder (alkaline) or 4 AA rechargeable cells and holder.

Experiment 2:– Calibration Of the Oscilloscope

No new or additional components needed above those for Expt. 1

Experiment 3:– Use of Oscilloscope as a D.C. Voltmeter

As for Expts. 1 and 2 plus:–

a) Two ½W carbon film resistors, 1 x 10k and 1 x 22k;

Experiment 4:– Series Connected Resistors

As Expt. 3 plus one additional 15k ½W carbon film resistor.

Experiment 5:– Using the Oscilloscope to Determine the Current in a Resistor

No additional components to Experiments 1 to 4 are needed.

Experiment 6:– The Wheatstone Bridge

Additional components needed:–

Resistors in Experiments 1 to 4 plus:–

a) 2 x 10k ½W plus 1 x 8k2 ½W
b) 1 x 10k horizontal Phier preset, PT15 size.

This concludes the parts you'll need for Experiments Book 1 covering Experiments 1 to 6!

Chris Williams

[Chris55000]

Hi!

Experiment 7:- Demonstration Of The Effect of an Alternating Voltage

a) Iron cored inductor (I can't find exactly what B.N.R.E.S. used originally, but something like an old battery valve output transformer ignoring the secondary would probably serve)
b) 2k2 ½W resistor
c) Wire–ended neon lamp

Experiment 8:– The Induced E.M.F. in an Inductor

No additional components above those for Experiment 7 are needed.

Experiment 9:– Magnetic Effects on the C.R.O.

a) One small bar magnet

Experiment 10:– Electromagnetism

a) One Experimental Inductor with steel rod core – (again I don't know what B.N.R.E.S. used exactly but the one below would probably suffice:–

https://www.ebay.co.uk/itm/133135291663

Experiment 11:– Generation of an E.M.F. or Voltage

No additional components other than those needed for Experiment 10 are needed.

That concludes the parts needed for Experiments Workbook no. 2 covering Experiments 7 to 11!

Chris Williams

[Chris55000]

Hi!

You will also need the perforated matrix board, pins, wire, etc., as given in the introduction.

Experiment 12:– The Bipolar Transistor used as an Amplifier

a) Three ½W carbon film resistors, 1 x 270R, 1 x 1k and 1 x 10k
b) One 0.47uF 250V polyester film capacitor (not used in Expt. 12 but wired for later use);
c) One 10k PT15 preset as for Experiment 6
d) One BFY50 transistor

Experiment 13:– The Use of A.C. Couplings

a) 1 x 0.1uF. 250V polyester capacitor

Experiment 14:– The Transistor as a Switch

No additional components to those needed for Experiment 13 are needed.

Experiment 15:– The Transistor Inverter

a) Two 2k2 ½W carbon film resistors
b) One 220R ½W and one 270R ½W resistors;
c) Two polyester film capacitors, 0.1uF and 0.47uF, 250V d.c. working;
d) Two BFY50 transistors;
e) The inductor needed for Experiments 10 and 11 in the previous post;
f) 0ne small reel, e.g., 2 ounces, of 28 s.w.g enamelled copper wire, 5m minimum;
g) One RM10 or similar pot core kit with bobbin

That concludes the components list for Experiment Workbook 3 Covering Experiments 11 to 15!

Chris Williams

[Chris55000]

Hi!

For the experiments described in this Workbook you will need the Transistor Inverter built in Experiment no. 15.

Experiment 16:– Resistors in A.C. Circuits.

2 x 15k ½W carbon film resistors.

Experiment 17:– Capacitors in A.C Circuits, Part 1

You will need:–

a) One 10k PT15 horizontal preset from Experiment 6;
b) One 0.01uF 250V polyester capacitor;

Experiment 18:– Capacitors in A.C. Circuits, Part 2

No additional components to those needed for Experiment 17 are needed.

Experiment 19:– Inductors in A.C. Circuits

You we'll need:–

a) One additional inductor of the type I suggested for Experiment 11 onwards, this makes two in total, one is needed in the Inverter;
b) 1 x 1k ½W carbon film resistor;
c) 1 x 10k PT15 horizontal preset from Experiment 6.

Experiment 20:– Resonance

Components needed are the Inverter from Experiment 15, the components from Experiment 19 plus:–

a) 2 x 1000pF polyester or polystyrene capacitors, 250V working;
b) 2 x 2200pF polyester or polystyrene capacitors, 250V working;
c) 2 x 4700pF polyester or polystyrene capacitors, 250V working.

That concludes the components needed for Experiments 16 to 20 in Workbook No. 4!

Chris Williams

[Chris55000]

Hi!

I will be providing the Experiments Workbooks for all 40 Experiments, either by scanning the original documents or re–typing the text on new ones.

Experiments 31 to 40 are conducted on a purpose–designed PCB called "DM1", if there's no Member who can locate an original drawing of one, then I can lay out an alternative that can be made on a standard piece of 100 X 160mm board.

Chris Williams

[Chris55000]

Hi!

According to the online resonance calculators I found, as an alternative, something like a 1.5mH or 2mH air–core speaker crossover choke (you would have to buy two to conduct all the experiments) with a round centre hole would fit the bill almost exactly, but if anyone's got all the yellow assembly and component documents, please feel free to correct me!

Chris Williams

[Red to black]

Thanks for taking the time and effort for doing this Chris

[Andrew B]

Chris, thanks for this, I am following this thread.

[Chris55000]

Hi!

I have now won and paid for a flatbed A3 scanner and awaiting it's arrival so the big monster pile of Manuals and the B.N.R.E.S. Lesson and Course books I have very recently received I'll be able to upload, all will be available free from my Dropbox in due course!

Chris Williams

[MotorBikeLes]

Chris (not intended to upset you) but I acquired an HP7500 officejet pro PSC from our local amenity site, FOC. Prints and scans in A3.
Similarly I previously acquired an HP8500A, like the above, but A4. That was the one I scanned the TQ pages for you. Also FOC.
I have thought about a self contained A3 flatbed scanner, but the prices frightened me to death. A NEW HP was £800 plus as I recall.
Les.

[Chris55000]

Evening Les!

They must be a lot more amenable in the I.O.M. tip–yards than they are at ours! – anything like that at mine rapidly gets squirreled away by the local council's tip yard staff – you try and ask anybody to give you something that looks semi–valuable at my tip and you get ordered off!

Not withstanding that tho', I have certainly noticed the prices of A3 flatbed scanners have been getting ridiculous now and nobody's letting 'em go b.i.n. these days? I'm sure you could get them for two figures a few years ago!

Any ideas why?

I did manage to procure one for £25 "spares or repair" and am hoping it is repairable!

Chris Williams

PS!

With regards to A3 printing, I try and format diagrams I draw to avoid it altogether as recommended by Chris Schroeder in his 1996 book "Inside Orcad for Windows", in which he emphatically deprecates formatting a diagram bigger than A4 (or "A" size in the US) because of the high cost of printing it – there is a firm that says it will print an A3 circuit diagram in colour for about £3.50 plus p & p, but the TQ idea of splitting up an A3 diagram over a two page spread is by far the best way of doing it!

Diagrams I produce are drawn to Thorn/BRC standards in use about the "TX9 and TX10" era – I went to great pains to measure and format my circuit symbols accordingly.

I now have acquired an original TQ D67 (not 'A') manual now added to my scanner pile!

[Chris55000]

Hi!

Further to all the above, I have found the Construction Documents for the B.N.R.E.S Oscilloscope were typed/published on an additional series of 20 "STEP" manuals with yellow first pages, and extra loose–leaf diagrams were supplied for the course students to fill in the answers and send back to be marked by the Course Tutor.

I didn't get these in my initial parcel of B.N.R.E.S. coursework books, but I now have a much larger parcel coming separately that will contain these!

Chris Williams

[ParcGwyn]

Thanks for doing this Chris, following with interest.

Dave
GW7ONS

[Chris55000]

Hi!

Update on this project – I have now received the full set of original Oscilloscope Construction Documents for the B.N.R.E.S. Mark II Transistor Oscilloscope with all the necessary diagrams, so I'll get scanning as soon as my leisure time permits!

Any Member who has, or comes across any remains of this in attics, sheds, etc., will be able to check everything's there, what was used, and how the wiring should have been carried out!

I don't have any information on the Mk I Valve Oscilloscope (2 x EF80) or the Valved course Experiments, as of yet, so it there's a Member who's got this, and either can scan the material, or has already done so, and can put it on CD, etc., or is willing for me to purchase, please PM me!

Chris Williams

[Chris55000]

PS!

Further to my Introductory post in this thread, 100 X 160 mm perfboard or matrix board is actually a bit smaller than was originally used, but you can buy a 2200 hole Perforated Board 160 X 115 mm that will meet the needs of these experiments, and I will be producing some additional redrawn layout sheets & dimensioned plans at a later date, if anybody actually fancies building this oscilloscope again!

A small "R Core" screened transformer with suitable h.t. and l.t. windings, about 40–50VA can be bought from the usual online suppliers, and 36 way tag–board of the original size and specification is still fairly plentiful!

Small round/rectangular CRTs suitable for this are still reasonably easy to obtain, and if anyone does want a suitable oscilloscope chassis with CRT, mu–metal screen and oscilloscope–type transformer to try these circuits out on, "Unilab" scope chassis are ideal for these!

Chris Williams

[Chris55000]

PPS!

As I haven't got the original Construction Details and Specification for the original EF80 two valve design, I can't be absolutely definite on this but I think the specs decreased a bit when B.N.R.E.S. made the design solid–state – the valve model has 4 Timebase Speed ranges, the Mk II Transistor Model only three.

Chris Williams

[Ed_Dinning]

Hi Chris, it was said that the 2 valve design was cribbed from the PW service manual design of "A TV Oscilloscope" using a VCR 97 and 2, EF50's.

Ed

[Chris55000]

Hi

Hi Chris, it was said that the 2 valve design was cribbed from the PW service manual design of "A TV Oscilloscope" using a VCR 97 and 2, EF50's.

Almost certainly the case, as the EF80 was basically the EF50 redesigned to use the new (at the time) B9A Noval Base.

As I said previously, I'm still looking for the Valve Oscilloscope build documents and the Valve Experiments books and diagrams – the Valve Oscilloscope had 400V h.t. and 6.3V l.t. outlet sockets intended for use with the experimental circuits used – in the Mk II Transistor Oscilloscope from 1979 onwards, the Experiments were entirely operated from one 4.5V (two 4.5V dual polarity supplies in Expts. 31–40) battery supply, and no external power outputs were provided in the Mk II version.

The Valve Oscilloscope had "X1" and "Y1" sockets on the front panel, (redesignated for 10V and 1V 50Hz outputs in the Mk II), so I suspect at least one, or more, of the Valve Experiments were amplifier, oscillator or T.B. circuits intended to be plugged into the X1 and Y1 sockets.

There's plenty of spare chassis–space and the three holes in the rear chassis apron still available for anyone who wants to add the two 4.5V supplies on an additional piece of matrix board tho' – I will provide a suggested write–up for this when the scans are completed and uploaded.

Chris Williams

[Chris55000]

Hi!

Looking through archived magazines on American Radio History, the B.N.R.E.S. advertising, which had always been a "full page advertisment", had dwindled to a small corner one by August 1985 and disappeared by December 1985 – can anyone else confirm they stopped selling the course by then?

During the last few months they advertised, their contact details changed from Reading, the one given on the course paperwork, to a P.O. Box address in Teignmouth, Devon.

Chris Williams