mined by the time constant of resistors R90
and R100, with capacitors C90 and C100.
The output signals from the collectors of Q9
and Q10 are fed to the primary winding of
audio output transformer T2. Capacitor C101
prevents any DC voltage from reaching the
transformer. The signal from the secondary
winding of T2 is connected across volume con-
trol R102. The wiper of the volume control is
connected to the speaker. The control my be
adjusted for the desired listening level.
If desired, the receiver output may be con-
nected between GND and the Receiver Audio
terminals. This allows the audio to be heard in
headphones connected to the Phone jack of
the Electronic Keyer. The speaker of the Elec-
tronic Keyer cannot be used when a receiver is
connected, as it is of too high an impedance
and cannot handle the output level of the re-
ceiver. If speaker operation is desired, the indi-
vidual speakers of the Electronic Keyer and the
receiver must be used.
Summary of Contents for HD-10
Page 1: ...HEATHKIT ELECTRONIC KEYER HD 10 ...
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