A more effective 'clicker'

Almost all simple Geiger Counter designs I've seen, use a piezo element or a small loudspeaker, to give the audible 'click'. Ive tested some of these, and to be frank I think they are rubbish! Yes they 'click' but its just the instant of the loudspeaker coil being pulled in. Its not very satisfying.

Since for some of my Geiger builds I'm wanting a simple count indication of this 'click' type, I decided to work out a design that would give a much nicer, cleaner, and louder indication.

The result is a single transistor design, which when triggered by a pulse from the G-M tube, switches a parallel arrangement of an LED, fed by a 1k series resistor, and a low cost miniature 5V buzzer. As this initial circuit is designed for 9V, there is a potential divider made of two 100Ω resistors which provides a roughly 4.5V supply for the buzzer. In order not to draw any current when not needed, the 'ground' connection of the potential divider connects to the buzzer negative, and so to the transistors collector.

To prototype this, I had to rob the buzzer from a cheap Chinese 'pixie' transceiver, that was lying about in the workshop. I also, belatedly, added a series resistor to the transistor base on the breadboard prototype - after destroying one transistor by repeatedly applying raw supply to the base! I also destroyed a few LEDs trying to find a way of using a capacitor to 'extend' the pulse.