Vacuum Tube - 6S4A, Triode, Medium MU
New-Old-Stock (NOS) tube. The 6S4A is a miniature medium-mu triode for use as the vertical-deflection amplifier in television receivers. The tube features relatively high plate current at low plate voltages and is capable of withstanding the high pulse voltages normally encountered in this application. The 6S4A also exhibits a controlled heater warm-up characteristic which makes it especially suited for use in television receivers which employ series-connected heaters. When the 6S4A is used in conjunction with other 600 milliampere types which exhibit essentially the same heater warm-up characteristic, heater voltage surges across the individual tubes are minimized during the warm-up period.