Philips Electronics EE8 and E20 Kits

 Philips Electronics EE8 and E20 Kits   

It was a dark mid winters Christmas morning back in 1964 in the days of snow drifts and coal fires when my life changed forever. 

 

Having tired of playing with my crystal set built from a circuit in Practical Wireless 

Radio Construction for the Beginner Page 584 November, 1960, with the one transistor amplifier powered by a 3v No8  battery described in Decembers copy,

N.B. All the parts were purchased from Stan Willets Spon Lane shop.

 

 

I awoke to see this electronic's EE8 kit.

I later brought the A20 add on kit and the LW coil pack purchased from Wulfrun Camp shop 

in Carters Green, also long since gone

 

Not forgetting a Short wave coil I made which allowed me I listen to the HF linked Gemini and Apollo missions from Spain and Australia .

                                                    EE8 Original box cover

          I replaced the Polystyrene with a set from a known internet sales site 

                                  

            Replacement polystyrene interior with New or original components 

                                           A new green lamp shade was obtained to 

                               With New Transistors and a period Diode from my own stock 

                                                                  Semi Conductors

                AF 116                                          OA79                                          AC126

Listed as RF (it was back then)             Germanium Diode                    Germanium Alloy

TO-7 case Germanium P-N-P         for FM detector Circuits       Medium Power AF Transistor

Alloy diffused junction Transistor      Max Reverse Voltage                         VCB   -32V

VCB  -20  Ic 10mA  hfe 150              Peak 45V Ave  30 V                            Ic 100mA

Power gain                                    Max Forward Current 100mA    Ptot max T= 75C  = 500mW

 (f =10.7 Mc/s = MHz ) 25 dB                   Average  4mA

 

It must also be remembered the AF  family of Transistors were also susceptible to the tin plating on the inside of the TO-7 can developing tin whiskers  which slowly grow until they touched the junction destroying the transistor from within 

The Manual

                                                          The Base Board 

                                                  Which 4 little plastic legs were fitted 

PARTS LIST

                        One of the 8 overlay Cards Marked “C1  a one Transistor Radio"

                         This is  a clever little circuit which amplifies the signal twice

 

 The ferrite Rod has two coils, one  is tuned to resonance (the frequency we want) by a Coil (t1&t2) which is connected to a variable Capacitor

The Coil and variable Capacitor gives a tuning range for the whole of the MW

 

 

A second Coil ( t3& t4) is the signal coil and the desired radio signal appears at the base of the transistor and gets amplified , appearing at the collector.

 

However this amplified RF signal cannot go through the choke ( inductor) as its gives a high impedance path to RF .

So the RF amplified signal takes the easier route through C11 and the diode where the Radio signal demodulated with any remaining RF filtered through C12 to ground

 

This new Audio signal goes through the second Coil ( t3&t4) again and again it gets amplified.

This new Amplified Audio signal appears at the collector but this time as at a much lower audio frequency, so  it can go though the choke ( inductor) and the signal can get to the ear phone

 

 

Enjoy 

 

 

 

                                          Source :- My own collection 

                                 and a few odds and ends from the Net 

Does it work ? Yes, Radio 1 has long gone from MW but the music is exactly the same