Getting Started With OpAmps \ Dynamic Microphone Amplifier

[@duncanmarks1590]

hi, good presentation with the very good addition of concepts that are not covered (i.e. slew rate etc). thank you. bye Duncan

[@hsc-pk]

Very well explained sir! I was consistently failing to get TL072 going with single supply - so the voltage divider was missing - thanks sir - datasheets could have given an application circuit. Thanks!

[@0033mer]

Glad it helped

[@sayantanmaiti2513]

A big thanks to you Sir for getting the concepts clear....if possible please continue the series with the topics you mentioned at 12:38...thanks

[@colinpamplin9976]

Very well explained. Thanks for sharing

[@kamelk8027]

Great explanation, keep doing electronics videos

[@douglasthomson2986]

Great explanation. Thanks for taking the time to make it.

[@mr.italosynth8520]

Love the video! I've made small op amps for microphones based on designs I've seen on the web but most of them are not clean like this is. I'll have to try this one out next. Quick question: If I wanted to make a LINE LEVEL AUDIO (600 ohm) Audio Distribution amplifier to take 1 input and drive 4 outputs with it, what would be the best combo of feedback and input resistors to use? (I'd like the ratio to be 1:1 in audio level so if I am driving a 1volt P2P 1000Hz Sine Wave on the input, I should have 1volt P2P 1000Hz Sine wave on each of the buffered outputs) I know each output would need a "buffer opamp" kinda like what you showed at 6:21 but I would just take the output of the first Op Amp and drive the NON-inverting in of all the 4 buffer op amps while the feedback is a direct line from the output to the INverting input for each buffer opamp. The idea is I want to take my audio from my computer and send it to a series of amplified speakers our other output jacks where I can connect test equipment to provide an audio source for my projects. Thanks!

[@iblesbosuok]

Great explanation way. Great video. Tantalum capacitors show your special taste.

[@0033mer]

Thanks!

[@segoetnico]

Thanks for this good info. It helps a lot understanding how op amp works.

[@joeritchey4348]

That was a great explanation!

[@SG-wj3nk]

Thank you for your amazing videos, they helped me a lot. I appreciate your great work.

[@0033mer]

You're very welcome!

[@grahamsound]

Great video. Thanks! I ordered the book.

[@0033mer]

You're welcome! Thanks for the visit.

[@ibendiben]

Great video. I'm struggling to understand the values of the capacitors. Aren't they rather high? Especially the filter to gnd. How did you pick these values?

[@0033mer]

The input and output capacitors determines the frequency response of the circuit. Input impedance is 2.7k so to get a -3db down response at 20Hz a capacitor of 2.2uf is used. The output load is not known so a larger value of 22uf is used. The 3.3uf capacitor is the filter cap for the voltage divider. This value will depend on how clean the power supply is. The RC time constant is 22k in parallel with 22k ( 11k )times 3.3uf.

[@ibendiben]

Much appreciated! If I would want to turn this circuit into non-inverting, can I apply my signal to the voltage divider midpoint, and tie the current input point to ground? Perhaps also remove the cap and resistor from the divider...? Or am I missing something crucial now...

[@0033mer]

You could simply feed the output to the second op-amp to get a non-inverting output. For a single op-amp circuit with a non-inverting output search online for typical schematic diagrams.

[@ibendiben]

@@0033mer ah, I never thought of that. Deals with the floating pins aswell. I did look for circuits online. And thought this is how I could swap ;) probably got a lot to learn still.

[@ibendiben]

Is this as simple as connecting pin 5 (non inverting input2) to gnd and the two outputs (one of first opamp as input for second, and output of second as feedback) to pin 6 (inverting input2)? Or do I need to add two 1k resistors, one to input and one to feedback? Hard to find this setup with two in one online.

[@SS-mj2mq]

Thank you much for sharing. Great video 👍👍👍👍👍

[@0033mer]

You're welcome! Thanks for the feedback.

[@SS-mj2mq]

@@0033mer you're very welcome I work on amplifiers and build them myself. I just like watching other people build and fix things we're all here together to learn right 😁🤗 And you can always learn something new from someone else there's so much to learn and know about electronics. And they're always coming up with something new and different that we can all learn about too LOL 😁 The audio world is constantly evolving.

[@attilarivera]

I do my pre-amplification using one transistor bc547. After pre amplification , it goes to the amplification. Now a days almost all small devices are projected to work on 5v, why 6 or 9 or 12v if u can use the own device power suply to power up the pre and microfone as well.

[@0033mer]

The video is a primer with a real application example for beginners. Once the theory is understood they can modify the circuit to fit their needs. I have other videos using transistors and even digital logic in linear mode: kzbin.info/www/bejne/l4S7p2l8mb6EnK8

[@attilarivera]

@@0033mer yeah i know. 🤗 Your video about Class A amplifier is cool. I have made a lot of anplifier for smartphones here 🤗 Thank you. 👏👏👏👏👏👏 💚💛💙🇧🇷🇧🇷🇧🇷

[@JSC-4]

Perfect, just what I needed!

[@0033mer]

Glad it helped!

[@amitghosh6966]

I built a circuit using Lm741 & used a small condenser mic of tape recorder to speak on it but the sound not very loud and I need to bring my mouth very close to mic. What's the problem please tell me?

[@0033mer]

The circuit for a condenser mic is different than a dynamic mic. Check your circuit, you might need anothe gain stage. kzbin.info/www/bejne/l4S7p2l8mb6EnK8

[@W1RMD]

Thanks for this great info!

[@0033mer]

Glad it was helpful!

[@amitghosh6966]

I made a preamp with 741 Ic and also with a single transistor with carbon condenser mic in both. The problem is I need to bring the Mic very close to my mouth to speak to record audio. What's the problem ? Is this Mic fault ?

[@0033mer]

Try an Electret mic. kzbin.info/www/bejne/l4S7p2l8mb6EnK8

[@ohmslaw6856]

How did you calculate the value of that 2.2uF cap? Is it a high pass filter?

[@0033mer]

The input impedance (Zin) of the circuit is 2.7k so the Xc of the capacitor at the lowest expected frequency should be less than 1/10 of Zin. Calculate C to be greater or equal to 10/6.28fZin For voice I like it a bit treble so it is not muddy so I used 260 Hz

[@lacasse4]

Could you explain how the microphone is connected to you circuit? Most dynamic microphones have 3 leads.

[@0033mer]

For balanced operation the third lead is the coax shield which is connected to chassis ground. For unbalanced operation the black wire is connected to the coax shield which is ground on my breadboard and the white wire is fed to the amplifier input. pubs.shure.com/guide/561/en-US

[@randomtech9293]

Very clear....

[@runelambert729]

can you also use electrolytic capacitors instead of ceramic capacitors?

[@0033mer]

Yes ... electrolytic capacitors can be used.

[@manofmesopotamia7602]

5:50 so basically, the voltage divider on pin 3 is meant to keep the amplitude of the signal voltage on the output of the op amp at 6 volt peak to peak?

[@0033mer]

It keeps the output at 1/2 Vcc so the signal can can vary above and below it symmetrically.

[@hamadyt956]

Best🎉🎉🎉

[@alexdem98]

What if you use 9V battery instead of 12?

[@0033mer]

Yes ... a 9 V battery will also work.

[@alexdem98]

@@0033mer But you'll get more noise/clipping?

[@ohmslaw6856]

Why is the input cap negative to positive? I thought it should be positive to negative

[@0033mer]

A dynamic mic is basically a coil so the input will basically be grounded DC wise. The 1/2 Vcc bias voltage is on the other side of the cap which is more positive. This determines the capacitor orientation.

[@alexdem98]

I don't understand where you connect you speaker on the breadboard

[@runelambert729]

look at the datasheet on alldatasheet.com you can see the pins over there. The - side of the microphone/speaker you connect straight to the pins of the tlc 272

[@numeric.alphabet]

So you won't what if 3M

[@numeric.alphabet]

Ember bukan tutupnya 3M

[@numeric.alphabet]

Tutup satu bukan tutupnya 3M