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Low noise Mini Electret Microphone PreAmplifier
- Rajkumar Sharma
- 42.175 Views
- easy
- Tested
- SKU: EL51787
- Quote Now
- 1 Likes
This single supply microphone pre-amplifier amplifies the output signal of an electret capsule microphone to audio line levels. An op-amp is used as a trans-impedance amplifier to convert the output current from the microphone into a signal-level voltage. The circuit works with 9V so it is a good choice for battery-operated systems.
Features
- Supply 9V DC
- Current Approx. 3mA
- On-Board Microphone
- Very thin and narrow PCB
Schematic
Parts List
Version v.2 with LV321
This v.2 of the above-board provides an additional option to use LV321 OPAMP in case you can’t find the OPA172. The board has two OPAMP footprints, and you should solder only one. If you use LV321 OPAMP, then the maximum input Vcc=5Vdc. If you use OPA172 OPAMP, then the maximum input Vcc=36Vdc.
Photos
Video
OPA172 Datasheet
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PCB
Thank you for this. Modified it to run on a 5V supply and using another OP-Amp and it works perfectly with those alterations.
Could you let us know what modifications you have done to this circuit and why?
the capacitor C5 is well polarized in the diagram, or is it a misprint
Thanks for noticing this fault. We fixed it above in schematic
I want to purchase the above microphone preamp. What is the cost in USD and how do I get it?
Thanks for your interest in this board. Please check your email for more details.
Hi! Is it possible to hear some real sound tests? is it possible to get a copy of this mounted for experimental purposes? thanks and good job!! 🙂
I am sorry, all i have for now is the video above, and we don’t have a sample on hand, but we can produce the board in quantity if you are interested.
Hi,
I’m interested in several of these — more if they perform well.
How is performance in the presence of RF interference & nearby electrical devices? The PC board is pretty basic — does it require shielding?
I am interested in either the PC board or assembled device, depending on price. Thanks!
Could you email me through the form here: https://www.electronics-lab.com/contact-us/ and I will contact you with a quote.
Hi!
How much for an assembled device?
For now I’m in a prototyping face and i would like to try one of these out.
Sorry, these will have to be produced on order, so our minimum is 10 boards. Will this work for you?