12AU7C is double triode small size novel tube, it is used as inverter drive push-pull amplifier in amplifying circuit.

Uf-----------------6.3(并) 12.6(串) V
If-------------------0.30 0.15 A

Direct Interelectrode Capacitances
                         No.1  No.2
input----------   1.6  1.6 PF
output----------   0.4  0.32 PF
grid to plate----------1.5  1.5 PF

Static parameter
Ua--------------100 250 V
—Ug-------------0 8.5 V
Ia---------------11.8 10.5 mA
Gm--------------3.1 2.2 mA/V
u--------------- 20 17
ri(approx)---------6.5 7.7 KΩ
Ug(approx)--------—11.8 —10.5 V
(when Ia=10uA)
class A1.maximum.single triode.
Ua----------------300 V
Pa-------------2.75 W
Ik(max)-------------20 mA
Ug----------------—50 V
Uh-k(pk)--------±200 V
with cathode bias----------------1 MΩ
with fixed bias-------------- 0.25 MΩ