Geiger Counter Parts List

Dl, D2 — Silicon rectifier,

Rl, R2 — l.0-ohm, l/2-watt

1000-volt PIV rating,
l-ampere (or higher) rated
current capacity, low reverse
current (20 microamperes
or lower)

carbon resister

R3 — 1,500,000-ohm, l/2-watt

carbon resistor

R4, R5, R7 — 560,000-ohm,

Ql, Q2 — NPN silicon transistor

l/2-watt carbon resistor

(2N3402 or equivalent)

R6 — 2700-ohm, l/2-watt carbon

Headphones — 2000-ohm high

resistor

sensitivity headphones

Cl — 0.0033-mfd, 600-volt

tubular capacitor

B — 6-volt battery with screw

terminals

C2, C3, C4, C5 — 0.47-mfd,

600-volt tubular capacitor

G — Geiger tube (A tube and

bakelite socket are available
for about $20 from The
Nucleus Inc., Box R,
Oak Ridge, Tennessee 37830.
Ask for tube-socket unit SG-2)

C6 — 0.006-mfd, 1600-volt

tubular capacitor

C7 — 0.047-mfd, 250-volt (or

higher) tubular capacitor

Perforated chassis board

T — 6.3-volt AC, 1.0 ampere

filament transformer

Push-in terminals

S1 — SPST toggle switch

Hookup wire

S2 — SPST normally open push-

Suitable enclosure

button switch