doel van R13 in B5X85A ? (Techniek Radio/TV)

door John Hupse † , Schoonhoven, 31.12.2014, 20:42 (3618 dagen geleden) @ Ouwe Schipper
Bewerkt door John Hupse †, 31.12.2014, 21:03

will this resistance R13 not decrease the total effective value of the volume control

Yes, it will decrease. The value of the volume control potmeter is 1 Mohm. The value of R13 is 270 Kohm. Together their value is 212 Kohm, which is less then 1 Mohm.

This is done to prevent the radio-signal sounding too loud compared to the signals coming from the pick-up and from the tape recorder.

In the fifties and sixties many radio manufacturers provided a physiological volume control on their sets. This type of control demands well-defined signal levels at the volume control potmeter.

how on earth would low frequencies pass through there

With s simple calculation you should be able to calculate the -3db point by yourself. The time-constant (product of R and C) is 3,3 x 1 = 3,3 ms. So the -3db point is 159 : 3,3 = 48 Hz. This is sufficient low for this set.

--
http://www.hupse.eu/radio