QUESTIONS & ANSWERS
best? What can I do to achieve a
longer, bigger spark?
— Mike Wandishin
AI reproduced your circuit in Figure 7. The main problem I see is D4, which limits the flyback voltage.
The primary voltage needs to be free
to go as high as
necessary to allow
the secondary to
generate the spark.
The snubber, R3
and C4, is a futile
effort because the
Jacob’s ladder is
radiating and
annoying the
neighbors, anyway.
The transistors
should be rated
200 or 300 volts; if
they blow up, go higher. R2 should
be connected to the Q2 emitter —
not to 12 volts — to protect the
base-emitter junction of Q2. The
higher the frequency, the better; as
long as it does not exceed the self-resonant frequency of the coil.
■ FIGURE 7.
:H;GRQ·W;MXVW;VD\;
our Geiger counters are accurate,
ZH;FDQ; 15&;FHUWLI\;LW;
Also Available
;8UDQLXP;2UH
;5DGLRDFWLYH;,VRWRSHV
;*HLJHU;&RXQWHU;7XEHV
;',<;.LWV;;*HLJHU;&RXQWHUV
;6OHG;DQG;,VRWRSH;KROGHUV
;$OSKD;3DUWLFOH;6SDUN;'HWHFWRU
,PDJHV;6FLHQWLÀF;,QVWUXPHQWV;;,QF;
;;;;;;;;;;;;;;;ZZZ;LPDJHVFR;FRP
External Wand
on GCA-07W only
7KH;*&$;;;;GLJLWDO;*HLJHU;&RXQWHUV;PDNH;LW;HDVLHU;
WR;WHDFK;QXFOHDU;SK\VLFV;ZLWK;LWV;SURYHQ;DFFXUDF\;
7KH;RQO\;GLJLWDO;*HLJHU;FRXQWHU;LQ;LWV;SULFH;UDQJH;
DFFXUDWH;HQRXJK;IRU; 15&;FHUWLÀFDWLRQ; NRC Certification Available Applications
;(GXFDWLRQ;±;&ODVVURRP;GHPRV;DQG;
;;H[SHULPHQWV;;*RYHUQPHQW;,QVWLWXWLRQV;
;(PHUJHQF\;6HUYLFHV;±;(07;;+$=0$7
;'RPHVWLF;3UHSDUHGQHVV;
;&RPSOLDQFH;9HULÀFDWLRQ
Features
;6HFRQGDU\;,QGLFDWRUV;±;DXGLR;;FOLFNV;;DQG;
;;;YLVXDO;;/(';;;$OVR;LQFOXGHV;77/;VHULDO;SXOVH;
;;;GDWD;SRUW;;KHDGSKRQH;DQG;H[WHUQDO;SRZHU;MDFN
;/RZ;%DWWHU\;,QGLFDWRU
;:LQGRZV;5DGLDWLRQ;*UDSKLQJ;6RIWZDUH;
;77/;6HULDO;WR;86%;&DEOH;,QFOXGHG
The Convenient All-in-One Solution
for Custom-Designed Front Panels & Enclosures
FREE
Software
ONLY $90.24
with custom
logo engraving
You design it
to your specifications using
our FREE CAD software,
Front Panel Designer
We machine it
and ship to you a
professionally finished product,
no minimum quantity required
;;;;; ; Cost effective prototypes and production
runs with no setup charges
;;;;; Powder-coated and anodized finishes in
various colors
;;;;; Select from aluminum, acrylic or provide
your own material
;;;;Standard lead time in 5 days or express
manufacturing in 3 or 1 days
FrontPanelExpress.com
1(800)FPE-9060
June 2013 29