Op Amp Radio


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Here is a simple radio that is easy to build and inexpensive. In fact, you probobly have all the parts you need in your junk box. You'll be suprised at the great reception with this little set.

Schematic

This is the schematic of the Op Amp Radio

Parts

Part
Total Qty.
Description
Substitutions
C11Tuning Capacitor
C210.1uf Disc Capacitor
R1110 Meg 1/4 W Resistor
D111N34 Germanium Diode
U11741 Or Similar Op Amp
L11"Loopstick" Antenna
MISC1IC Socket, Crystal Earphone, Wire, Antenna

Notes

  1. The antenna can be a piece of wire or a telescoping antenna. 18 inches is a good length for in the city.
  2. The tuning capacitor is a regular broadcast band tuning capacitor. I got mine from a junked AM radio. I got the loopstick antenna from that same radio.
  3. You can change L1 and C1 to recieve different bands (eg. Shortwave). To recieve shortwave, try this: Make L1 30 turns of 30 guage wire wound on a film can and make C1 a 10-365pf capacitor.
  4. Combine this circuit and the 8 Watt Audio Amp for a really neat radio.

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Comments

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anonymous
Op Amp Radio
Thursday, October 17, 2013 3:30:11 PM
I built a similar radio many years ago, using a mosfet opamp from RS, a TL 7611 I think. Feedback resistor was 100M ohm! So powerful on 1.5v, it didn't need external antenna!
advisor
Op Amp Radio working
Monday, October 01, 2012 10:52:00 AM
TO ALL VISITORS this schematic may not work. This is a similar op amp radio try it http://www.youtube.com/watch?v=3Zzmi_Kno4w&feature=fvwrel
SJN
Op Amp Radio
Friday, August 10, 2012 1:20:00 AM
cn any1 plz tell the specificatn's of the loopstk antenna used in the circuit...n y is an crystal ear ph used here..???
divyesh
Op Amp Radio
Thursday, July 14, 2011 1:13:44 PM
how it works....how it tune different frequencies...if i want 98.3Fm....how i can choose?....what about coil...& its value..?..can we use speaker instead ear phone...???
Stone
Op Amp Radio
Thursday, June 02, 2011 3:53:19 AM
It is best to use an LM386 OP AMP for this circuit to work but this circuit is very delicate. You get best reception at night. The 365 variable capacitor is very Important. I also used a 220 uH inductor.
rajesh
Op Amp Radio
Saturday, February 19, 2011 4:15:08 AM
bull shit this dosn't work whats the value of the goddam coil in that shit ckt of yours. if you dont send me the value right away i assure you will get a nice spanking from me.

(Editor's notes: Approved because this comment is awesome.)

jon
Op Amp Radio
Thursday, November 25, 2010 4:21:14 AM
Just built this set with great results. To decouple and increase the 'Q' just wrap a few turns of the aerial wire around the coil. Used an R.F choke instead of a coil for S.W listening. In reply to KDB5IH, ebay is my usual source for variables.
KD5BIH
Op Amp Radio- components
Thursday, November 11, 2010 11:03:06 PM
Hi! I've heen a ham since 1997. But, I have been in electronics almost 50 years (back in the tube days)! 10-365pf variable caps are getting really harder to find.. Any suggestions?? 73 KD5BIH
anonymous
Op Amp Radio
Friday, September 17, 2010 1:10:39 AM
i ve tried this ckt but failed to get the output..can anythin be used to modify d ckt n get a better output? also give some information abuot how to tune the ckt.
anonymous
Op Amp Radio
Wednesday, April 14, 2010 1:39:53 AM
ve tried this ckt but failed to get the output..der is sum sort of disturbance obtained in d end..can anythin be used to modify d ckt n get a better result?
anonymous
Op Amp Radio
Tuesday, April 13, 2010 8:09:31 AM
okay pls help me out how shuld i make it ?? i tried connecting all d components even used a circular kinda antenna and headphones as output but still its not working n also tell me exactly which tuning capacitor to use i got a 500pf one wid 3 terminals n used inductor wounding it for 30 rounds still not able to get it plsss plllss i need helf need to make it asap!
anonymous
Op Amp Radio
Wednesday, January 27, 2010 10:58:35 AM
Are you supposed to connect Vcc to the Vcc pin on the op-amp? Otherwise, where?
Subhajit
Op Amp Radio
Wednesday, January 06, 2010 10:59:01 AM
My model of OP-AMP radio is catching a lot of noise. How can I boost the signal to noise ratio? I think the problem lies in impedance mismatching with the antenna. Is it so?
cooltech
Op Amp Radio
Tuesday, December 29, 2009 12:33:23 PM
simple circuit but what about the output its working or not ?
JEREMY
Op Amp Radio
Saturday, November 14, 2009 4:43:42 PM
You can use any coil or LC circuit that you might find for crystal radio designs on the web. LM386 amp works great with a small speaker. Can someone post coil spec's for SWL coverage.
kuldeep
op amp radio
Thursday, August 20, 2009 7:28:04 AM
what is a loopstick anteena
dhana
Op Amp Radio
Saturday, July 18, 2009 5:24:52 AM
can u tell me about the loop stick antenna ana L1 in the figure
keith
Op Amp Radio
Monday, March 09, 2009 7:43:04 PM
I'm only getting one station.. wonder whats hooked up wrong, or if this radio is only supposed to get one station. But i have it hooked up to a push pull transistor audio amp n speaker i had already built on breadboard for my psp and that one station comes thru loud and clear. And i have a 4 wire loopstick plus a 6 pronged tuning cap. one sides for am the other for fm. not sure how thats all supposed to go.

(Editor's notes: Place a 1K resistor in parallel with the detector.)

08ES 25 MUET,PAKISTAN
Op Amp Radio
Monday, March 09, 2009 2:56:48 PM
THE PURPOSE OF GERMANIUM DOIDE IS TO DEMODULATE THE SINGNAL OBTAINED FROM LC-TANK CIRCUIT, WHICH IS BEING CHARGED BY EMF INDUCED IN ANT BY SIGNALS. GERMANIUM DIODES ARE MORE SENSITVE BCZ THEIR BARIER IS LESS(0.3V) AS THAT OF SILICON(0.7V). OP-AMP SIMPLY AMPLIFIES DEMODULATED SIGNAL FROM DIODE.
anonymous
Op Amp Radio
Monday, February 09, 2009 6:31:07 AM
IN FIGURE THERE IS SYMBOL OF INDUCTOR & ANTENNA, BUT IN DESCRIPITION L1=LOOP STICK ANT:, SO WHATS VALUE OF INDUCTOR ITS VERY CRITICAL PLEASE SOMEBODY EXPLAIN IT, FROM T.LAMZON
anonymous
Op Amp Radio
Monday, February 09, 2009 6:25:43 AM
PLEEEEEEZ SOMEBODY TELL ME ABOUT ANTENNA. IS IT PIECE OF WIRE OR SOME SORT OF INDUCTOR? PLEEEEEEEEEZ GIVE DESCRIPTION. THANKS IN ADVANCE.
anonymous
Op Amp Radio
Thursday, January 15, 2009 12:39:31 PM
CAN I GET A PICTURE OF THE CIRCUIT W hich HAVE BEEN BUILT ALREADY AND ALSO THE TUNING CAPACITOR AS 6LEGS AN I WAS WONDERING WHICH LEG SHOULD I USE SINCE THE CIRCUIT REQUIRES 2 LEG PLEASE HELP ME OUT
anonymous
Op Amp Radio
Thursday, January 15, 2009 12:27:48 PM
what is the purpose of the 1n34 diode? can i use any diode or do i have to use that specific one? let me know...
texassignaltech
Op Amp Radio
Thursday, December 04, 2008 9:44:06 PM
The purpose of the 1N34 germanium diode is to detect and recover the transmitted audio frequency modulating signal, from the radio frequency carrier signal. Try to find a 1N60 germanium diode which should perform equally as well as the 1N34. What is important here is that you use a germanium type diode as opposed to a silicon diode. The germanium diodes have greater sensitivity to lower levels of rf energy.
SANYI
Op Amp Radio
Thursday, November 27, 2008 10:54:08 AM
I couldn't find fm in description. Short wave is not always fm. I've built the circuit. Works well. You can replace the germanium diode with 1n914 or other germanium diode as well. It's demodulate the signal. The 741 is an audio amplifier. C2 used for DC decoupling.
Greg
Op Amp Radio
Tuesday, October 21, 2008 2:39:59 AM
whats the funtion of in34 diode and its equivalent i tried 2 get one bt cannot find one
Spartan
Op Amp Radio
Friday, October 10, 2008 2:17:12 AM
we tried it. the op amp is working but no radio signal could be received. we tried it here in the Philippines.. what's wrong with it?
anonymous
Op Amp Radio
Sunday, September 28, 2008 11:39:01 AM
can we make this without using crystal amplifier??? and use normal earphones??
anonymous
Op Amp Radio
Monday, September 01, 2008 6:04:55 PM
I made this in 2 hours and combined it with a LM386 audio amp IC. WOW WORKS GREAT!!! If you don't have a ferite loop stick you could wind about 120 turns of 22ga wire on 2.5 inch form about 6 inches long. This is basicly a souped up crystal set ...
anonymous
Op Amp Radio
Tuesday, August 26, 2008 4:26:18 AM
tried, op-amp is working, which could provide adequate sound output, but the receiver part is not working, no radio station can be found, i use loopstick antenna with a variable air capacitor, antenna length 18'' as suggested. what's wrong? (I'm in Hong Kong)
SHIBU B
Op Amp Radio
Monday, July 14, 2008 7:04:49 AM
It is really wonderful to hear that we can make fm radio using IC 741
anonymous
Op Amp Radio
Saturday, May 31, 2008 2:18:48 PM
by applying 324 opamp, can we build an extra output stage and use speaker?
incromatical
Op Amp Radio
Sunday, May 18, 2008 2:50:48 PM
what is the purpose of the 1n34 diode? can i use any diode or do i have to use that specific one? let me know...
anonymous
Op Amp Radio
Thursday, May 15, 2008 5:59:35 PM
can i change the 1N34 Germanium Diode what is her similar Diode if possile help me
Paul jayanta
Op Amp Radio
Wednesday, April 30, 2008 12:30:36 PM
If by using 741 ic we can make a fm radio that will be great.
ganesh
Op Amp Radio
Thursday, March 27, 2008 8:25:28 AM
what is mean by loopstick?.can i made this inductor as hane work?
Ado_PO
Op Amp Radio
Monday, March 24, 2008 9:20:39 PM
Tried it, worked well for a wirenest, OP drove a pair of old morse training headphones paralel conected so there is a 2kohm load. I didn`t find a 10Mohm rezistor so I used a serial chain of trimers. For the LC I used the coil that`s described and a tuning capacitor that goes up to 380pF. I have the negative pole grounded and the antenna is a bit of a wire that goes across the room near the ceiling.Selectivity is really a bother as I heard morse from the shortwave and even commercial FM stations. But that must be because of the local transmition station placed a few km away.
acegard
Op Amp Radio
Monday, February 18, 2008 5:35:54 PM
can i use a LM324? if so could anyone give me a schematic??
anonymous
Op Amp Radio
Friday, January 18, 2008 5:00:02 PM
does this circuit really work. if so, how well?
JASON
Op Amp Radio
Monday, January 14, 2008 12:54:23 PM
HELLO,TO PICK UP SHORT WAVE CAN YOU EXPLANE FILM CAN PLUS IT SIZE.THANK YOU FROM JASON
anonymous
Op Amp Radio
Thursday, January 03, 2008 2:13:12 AM
what is the value of inductor?
pram
Op Amp Radio
Tuesday, November 20, 2007 9:44:50 AM
give details about the crystal air phones
anonymous
Op Amp Radio
Monday, November 19, 2007 5:21:08 AM
kwame,try 10-20 turns on 1inch pill-bottle
Anurag
Op Amp Radio
Tuesday, November 13, 2007 2:57:56 PM
can anybody send me the exact ckt diag of a digital quality fm radio having surround sound output that is generally used in mobile fones

(Editor's notes: Good luck with that...)

kwame
Op Amp Radio
Saturday, November 10, 2007 9:37:46 AM
i need to do this. some one tell me about the loop antenna. how many turn do i need.
Giacomo
Op Amp Radio
Friday, October 26, 2007 6:11:37 AM
I reccomend to keep terminals 10Mohm VERY SHORT. The best thing is welded directly onto 741, otherwise the gain drops significantly. The circuit in this case works well
Ali Al-Roomi / Bahrain
It is purly theoritical circuit
Sunday, September 16, 2007 9:13:59 AM
I don't think it will work as good as you respect it!! It depends on an Operational Amplifier IC (LM741) & that kind of ICs doesn't have the ability to give a good result "sound" Similarly, we can't replace LM386 with LM358, because the first one is a sound amplifier while the other is same as 741 IC I recommed you trying to use LM386 instead of LM741, with changing the resistors, capacitors... etc
anonymous
Op Amp Radio
Thursday, September 06, 2007 3:34:43 PM
a 10-365pf varicap can be found in most cheap am radios experiment thats how to find things out the 10-40 try 5-30pf from internet electronic suppliehouses
anonymous
Op Amp Radio
Thursday, September 06, 2007 3:24:58 PM
1n60's are available from scott lowe at his web site www.comtrolauto.com
anonymous
Op Amp Radio
Thursday, September 06, 2007 3:19:50 PM
i was told an 1n60 diode is better, radio shack can order 1n34a if you can get them off the cell phone kick and do something
anonymous
Op Amp Radio
Thursday, September 06, 2007 3:15:27 PM
does anyone have a simple police band-150mhz-160mhz circuit tuneable,saw one way back when need for all wave radio im building 9v+ please post one
ravmonster
Op Amp Radio
Saturday, September 01, 2007 4:29:43 AM
i build a crystal radio using an op amp but it did not work: even you remove the op amp it just work the same when it has an op amp
anonymous
Op Amp Radio
Friday, August 31, 2007 2:15:28 PM
what freqs is the loopstick for? am?
mic2x
Op Amp Radio
Friday, August 24, 2007 10:34:17 PM
Your circuit didn't work here. Do you have a fm radio schematic that uses SC1088 IC?! please mail me!! thanks
PROF
Op Amp Radio
Friday, August 17, 2007 2:39:21 AM
OK! This is very interisting, Tjobela you raquire a multistage amplifier which I just so happen to be able to design. Contact me.
ananddharme
Op Amp Radio
Monday, August 06, 2007 7:40:30 AM
this is very good and small ckt of chip ic ,i will try it
jamiro
Op Amp Radio
Wednesday, July 11, 2007 8:39:55 AM
your circuit had a great apperance when being used with an amplifier
anonymous
Op Amp Radio
Monday, July 09, 2007 6:28:36 AM
poor circuits not good result
SARTH
Op Amp Radio
Saturday, July 07, 2007 12:54:15 AM
hi can i get some information about some simple receiver that has a bandwith between 80mhz to 110mhz
Danish Manzoor
Op Amp Radio
Monday, June 04, 2007 3:06:25 PM
i couldnt find 1N34 Germanium Diode, is there any alternative?
Roger D. Sand
Op Amp Radio
Sunday, June 03, 2007 8:52:51 PM
Interesting, I wonder if everyone realizes that this is a original crystal radio that uses a germanium diode rather than a catwisker on a crystal. Those could drive a high impedance headphone but those are hard to find now. The op-amp helps drive a modern low impedance ear piece.
Thobela
Op Amp Radio
Wednesday, May 30, 2007 11:01:59 AM
hi sir i need a audio amplifier circuit to drive an 8ohm speaker
Thobela
Op Amp Radio
Wednesday, May 30, 2007 10:58:20 AM
I'm Thobela Nqodumo an electrical enginnering student at WSU university in East London i'm doing a final year,in project that i'm currently doing is the two channel simplex communication system so i would appreciate if u can help me in the audio amp part which will use op amps to drive a 8ohm loudspeaker.Thank u
Hamad
Op Amp Radio
Tuesday, May 29, 2007 10:10:49 PM
I have done this circuit and i found it very usefull and i have listen to some channels thanks for giving this simple circuit
Dave
Op Amp Radio
Thursday, May 24, 2007 9:25:43 PM
I had good luck with this little circuit, but, for me, the crystal earpiece was too shrill so I followed it with a Lm386 and use regular headphones. I never could get it to work well on the broadcast band so made coil with taps to cover from about 5.8 mhz to 10 mhz. Most international stations come in well--big problem is overloading and really poor selectivity which I don't know how to cure.
anonymous
Op Amp Radio
Monday, May 21, 2007 5:03:05 AM
it is good,but ineed high rang FM reciver ,pls mail a 88-108MHz reciver,
SAIFUL
Op Amp Radio
Saturday, May 12, 2007 11:43:40 PM
this is a highly informative and easy circuit to get the desired frequency . i bless its designer.
melchizedek
non inverting amplifier
Friday, May 11, 2007 1:10:04 AM
please help me with a circuit diagram of a non inverting operational amplifier using a 12 v transformer as part of power supply
solomon
Op Amp Radio
Tuesday, May 08, 2007 10:09:38 AM
hello i need simple fm reciver diagram with explantion.to make in my home? thank you for your help
anonymous
Op Amp Radio
Tuesday, May 08, 2007 8:40:16 AM
i dont think that there exists a 10-40pf cap letalone a 10-360pf cap!
anonymous
Op Amp Radio
Sunday, May 06, 2007 5:13:03 AM
he gave simple circuits thanks for giving
rishi
Op Amp Radio
Thursday, April 26, 2007 3:06:23 PM
hi can u send me the circuit (used in cell phones) of a normal FM radio used mostly........??
alok
Op Amp Radio
Thursday, April 19, 2007 8:56:29 PM
sir could u pls email me the circuitry of simplest fm reciever with detailed description of each components ... and could you pls tell how to make inductor from gauge wire ..i m a beginner , so pl bear. thanx
Fawad Zaib
Op Amp Radio
Wednesday, April 18, 2007 5:03:56 AM
i have made dis cct n i found no eror in dis cct ..
anonymous
Op Amp Radio
Thursday, April 05, 2007 5:17:10 PM
Can you please comment on the comments. I am saying answer every commentor next to his comment thnax

(Editor's notes: You're kidding, right? If you have a question, use the forum.)

Arun prasad g b
simple FM Radio Circuit with high gain amplifier circuit
Monday, April 02, 2007 6:31:05 AM
hi ..i am technician please send me FM circuit with components details...
Keith V
Op Amp Radio
Tuesday, March 27, 2007 8:10:39 AM
If you tap diode 2/3 of way up tunned circuit, loss in voltage is offset by rise in Q - better selectivity. Suggest you try an RF bypass C on diode output and use non-inverting op-amp input for possibly higher gain but certainly improved signal-noise ratio. Hope this helps. Found your page well worth a look and have saved many items. Frequency counter/probe VERY interesting. Have you tried HC counters for more speed?
atiqbaloch
Op Amp Radio
Tuesday, March 27, 2007 4:34:42 AM
hi,sir i need a simple cicuit of fm radio,plz send me on my email add.i will b thankfull 2 u
anoymous
Op Amp Radio
Saturday, March 10, 2007 9:13:22 PM
is there anymore information about this circuit in detail if there is please email me with information.
aamir
airband radio reciever circuit required
Saturday, March 10, 2007 8:29:17 AM
hi, i need simple airband reciever cicuits if u have plz send me thanks
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