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
