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UCH42

Sensibly equivalent to:
141TH 14K7 X142
See also:
New valves from Mullard
    
Extras ▼

 

The UCH42 is an early all glass triode hexode from 1948 and was designed as oscillator and mixer for superhet receivers, and the hexode section was designed to operate with an AGC control voltage. The 100 mA heater was intended for universal (AC/DC) sets, and this explains the low anode voltages. Mullard do not give a frequency range for this device, it is, therefore unlikely to be greater than HF as the valve predates VHF broadcasting by more than a decade. Mullard also say that the UCH42 may be used as a phase inverter. The ECH42 does the same job but with higher anode voltages and lower current.
The triode oscillator had to supply a peak to peak insertion voltage of 13 Volts.
The valve is marked with the Mullard logo and was made in Holland by the parent company Philips.
The overseas origin is clear but this exhibit does not have the pejorative Foreign added to it.
Through the end wall in the screen can be seen the wire grids and lower down the strap the connects the two small plates that form the anode. The locating pip is moulded into the glass and no metal skirt is needed.
The thin glass tube envelope is 21 mm in diameter and, excluding the B8A base pins, is 53 mm tall.
References: Data-sheet & 1040. Type UCH42 was first introduced in 1948.

 

Pin Connections
B8A
1
2
3
4
5
6
7
8
h
a
a(t)
g(t),g3
g2,g4
g1
k
h

 

Absolute Maximum Operating Conditions
Hexode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
14
0.1
200
85
-2
3
3
1M
0.75

 

Absolute Maximum Operating Conditions
Triode
Va
mAa
100
3.1
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated October 26, 2020.
shape:thin.glass.tube construction:all.glass type:triode.hexode age:1940.1950 base:b8a heater:100ma pins:8 pin:1.h pin:2.a pin:3.a(t) pin:4.g(t).g3 pin:5.g2.g4 pin:6.g1 pin:7.k pin:8.h
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