VACUUM TUBE TESLA COIL WITH GU81M TUBE
BACK TO HOME
Finaly I have a GU81M tube for a new VTTC.
GU81M DATASHEET ----search here:
FIRST LIGHT
Input: 2100 VDC@ 1kVA rectifyed half wave+, WITHOUT DOUBLER (I don't find suitable caps).
Results 5-6 inches arcs to ground.
Pics were made with a russian FED3 camera on Kodak film ISO 200, f= 5.6, 1/2 sec exposure time.
SCHEMA
MOUNTAGE PICTURES
STREAMERS
ARCS TO GROUND
NEXT STEPS: VOLTAGE DOUBLER, STACCATO CONTROLER
SECOND LIGHT
Modifications: doubler built with some electrolitic caps in serie, another secondary (3 inches diameter, 9.6 inches wound lenght, 960 turns, F res = 522 kHz), new topload (metalic semisphere from an electric bell with a screw as nail), primary cap = 1.4 nF@ 14 kV (polietilene type), grid 1 resistor = 112 kohms@ 100 watts, screen grid resistor = 42 kohms@ 400 watts.
RESULTS: 8 INCHES STREAMERS, 10 INCHES ARCS TO GROUND
MOUNTAGE AND DOUBLER SCHEMA
STREAMERS
ARCS 1 (for comparaison, the copper rod used has a 1.5 cm diameter)
ARCS 2
NEXT STEPS: staccato, toroid as topload, a higher inductance secondary.
Many thanks for
Steve Ward
and
Steve Connor
for their help
THIRD STEP
Adding topload capacity (nice "pagode" style topload), better tuning, new position for grid coil.
RESULTS : 12 INCHES  (30 CM) SPARKS
STREAMERS
ARCS
DO NOT TRY THIS AT HOME......!!!
BUILDERS: ME AND COSTY
Many thanks for Costy: he gave me the GU81M tube.
NEW DESIGN HERE: 18-20" SPARKS