Tesla coil Tuner

I've built this small by very useful circuit to help me tune my first Tesla coil.It was designed by Terry Fritz.You can find the schematic here.

I've used one 102 tantalum capacitor here (1nF) because my coil is rather small.For bigger coils use twice the capacitance (two 102s in parallel).You may need even less capacitance than the 102 has.

Tuning the secondary.
First break the connection between the ground wire of the secondary and ground.Connect one lead to secondary ground wire and the second lead to ground.Next turn the POT.It should have multiple bright spots.The brightest spot is the resonant frequency.

Tuning the primary.
Remove the secondary.Connect the two leads in parallel with the discharge capacitor.The least bright spot is the resonant frequency.Don't forget to short the spark gap.

If the LEDs do not behave as described above chances are you out of frequency range.You may need to increase the capacitance of the tuner by adding another 102 capacitor in parallel with the one in the circuit.

Parts I've used
NE555 IC
two 10uF electrolytic capacitors
two LEDS green and red
two 470ohm resistors
one 102 tantalum capacitor
5K potentiometer (POT)
9Volt battery
switch

Here is the actual pcb.

Notice that when I connect the two probes together with an aligator clip both LEDs light up.That's a sign that the circuit works.

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