I need an circuit for a simple audio input signal indicator for a small 3 channel mixer. I just want to be able to know when I have a audio signal coming into the channel.
look up a comparitor circuit. Can be done with with cheap (or expensive) opamps. but comparitors like LM393 are best. you can also get the LM3915 chips and have a VU meter.
Dave
Dave
I'm looking for something simple with a low parts count. Could you direct me to anything specific?
lm391x LED drivers
strip of rectangular LEDS, or discrete LEDs.
Did you try looking up lm3915 after that previous posting?
What's the point of asking if you are not prepared to listen?
strip of rectangular LEDS, or discrete LEDs.
Did you try looking up lm3915 after that previous posting?
What's the point of asking if you are not prepared to listen?
The point is I need something cheap, and simple. The lm3915 is too much for what I want, it is also an obsolete chip. All I want to do is know when an audio signal is present on a mixer channel. One single LED. Something like this peak indicator circuit.
from Extreme Circuits that I just found.
from Extreme Circuits that I just found.
You meant LM339
Thats about as cheap and simple as it gets.
But I like the Samsung chip KA2281. It has hysteresis that the LM39xx chips do not have.
It only drives 5 LEDs which makes it simpler to build.
Thats about as cheap and simple as it gets.
But I like the Samsung chip KA2281. It has hysteresis that the LM39xx chips do not have.
It only drives 5 LEDs which makes it simpler to build.
Last edited:
Surely the transistors will operate at 12V. The pot will probably have to be re-adjusted and/or changed to a higher value.
The advantage of hysteresis in an audio display is that at low passages the LM39xx LEDs will flicker.
Whereas, with hysteresis, the LEDs are either full on or full off. Some people like this display better and professional equipment often uses this technique.
The advantage of hysteresis in an audio display is that at low passages the LM39xx LEDs will flicker.
Whereas, with hysteresis, the LEDs are either full on or full off. Some people like this display better and professional equipment often uses this technique.
How about 3 DPDT relays, with an LED parallel with the coils, rotary switch to switch from relay to relay.
Attachments
- Status
- Not open for further replies.