▼ Menu

4-THA

Sensibly equivalent to:
A36C AC/TH1 TH4A TH4B
    
Extras ▼

 

The 4-THA is a triode hexode frequency changer designed for AC sets that were fitted with mains transformers, for AC/DC (universal) sets the functionally identical 203THA with a 200 mA heater was also issued.
The triode is employed as the local oscillator and the hexode for the mixing process, the input signal being coupled to the control grid via the top cap for maximum separation of the circuits.
The classic envelope is 44 mm in diameter and, excluding the B7 base pins, is 117 mm tall.
References: 1043. Type 4-THA was first introduced in 1938.

 

Pin Connections
B7
1
2
3
4
5
6
7
tc
a(t)
g1(t),g3
g2,g4
h
h
m,k
a
g1

 

Absolute Maximum Operating Conditions
Hexode
Vh
Ah
Va
Vs
Vg
mAa
mAs
gm
4.0
1.5
250
100
-2
3.5
5.5
0.85

 

Absolute Maximum Operating Conditions
Triode
Va
mAa
100
1.5
Updated January 07, 2013.
Return to Main Index