[LectronFanModerator]

Hi all,

Yesterday, I was experimenting with the high tension transformer and found a neat usage for this : a simple VU meter !
The circuit makes use of the modified (and thus better performing) amplifier module and some modules.
The speaker is used as a microphone. The picked up noises are heavily amplified in the 2-stage amplifier module.
The amplified signal is then coupled to a transistor which has the high tension transformer as an active load.
We also use the already familiar 120 Ohm and 100µF capacitor to set the DC component in our transistor.
Without these, a too large current would flow and our transistor will be destroyed.

The neon lamp is connected to the transformer.
The circuit is so sensitive that it will pick up any whisper and noise and the cool part is that the neon lamp indicates the audio levels by not only glow brighter, but also with the change of glow length along the 2 tiny electrodes inside the lamp
Try for yourself and be surprised !
Here’s the circuit with a mixture of modern and legacy parts :

And here a setup with only legacy parts :

• This topic was modified 4 years, 10 months ago by LectronFan.
• This topic was modified 4 years, 10 months ago by LectronFan.
• This topic was modified 4 years, 10 months ago by Michael. Reason: Changed font and size styling for easier reading

[MichaelKeymaster]

Hi Frank,

This is so much fun!  Not only the brightness but the energizing length of the electrodes is very engaging.

Very cool 🙂   M.

[GuentherParticipant]

Hi Frank,

a very usable circuit – I found a not very good performing transistor block with this method – by the way…

I am am thinking on a special block with the HV transformer and a longer neon bulb, perhaps with a Fresnel lens (and a reflector ?)  for a better reading / viewing of the length / strength of the light as an indicator for the amplifier performance…

Let’s see what the next Corona days will happen 🙂 there is nothing to do else – so let’s work with Lectron!

Best,

G.

[GuentherParticipant]

The HV transformer had 2 broken wires and I couldn’t repair it – so I decided to build a special block with this defect part and a longer neon bulb. At this moment I didn’t find any pleasing reflector and / or a lens in my assortments, so this is the actual version:

In deed – a very nice idea, thank you, Frank!

Best,

G.

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