[Photo] 4 components make mini wireless FM microphone

Seeing the picture above, it is too simple. The circuit uses very few components, and only four of them form a miniature wireless FM microphone. The working frequency is relatively stable, the transmission distance is more than 10 meters, and the current is less than 0.5mA when 1.5V power is supplied. Such energy-saving microphones are rare. The distance can reach 30 meters with 3V power supply.
The circuit is shown in the figure, BG and L and the junction capacitance of the triode constitute a high-frequency oscillation circuit. The junction capacitance of the triode is about 2 ~ 3P. To make the frequency fall within the FM range, the coil should be wound around a 5mm diameter core for 7 turns. The vibration of the time modulates the high-frequency signal to generate frequency deviation and realize frequency modulation. The launch distance is related to the working current of the launch tube. The resistance can not be too large or too small. Between 300 and 500 ohms, the power is less than 1 milliwatt.
When choosing BG, the fT of the tube must be greater than 300MHz. If the 2SC3358 high-frequency tube is used, the frequency is more stable and the distance will be farther. The inductance L is divided into two coils to be wound, but the winding direction must be the same. L1 uses a 0.5mm diameter enameled wire to wind 4 turns on the 5mm diameter skeleton, and L2 winds 3 turns. The antenna can be used with a 10cm long flexible wire. When you touch the antenna, it will affect the frequency change. It is very stable when used in fixed locations.

This circuit can be installed in the cap of the small ink bottle, or in the pen cover. The battery uses A13 size batteries or smaller, but pay attention to adding a switch when using small-capacity batteries.

In-depth analysis of the first-level cache and second-level cache of the technical zone CPU eMMC mass burning dilemma, do you really know? Isolation flyback and non-isolated BUCK application design plan Schottky barrier diode selection and application guide How to use Altium in program design Designer puzzle?

Follow WeChat

Interesting and informative information and technical dry goods

Download Audiophile APP

Create your own personal electronic circle

Follow the audiophile class

Lock the latest course activities and technical live broadcast

comment

Publish

related suggestion

A simple FM microphone

The circuit (see figure) uses a capacitive feedback oscillator, whose frequency is stable and adjustable. Its feedback ...

Posted at 2006-04-16 19:24 â€¢ 286 times read

[Photo] Two FM microphones with voltage regulator circuit

Published on 2006-04-15 21:00 â€¢ 234 times read

[Photo] Another FM microphone

When watching TV late at night, you usually have to lower the volume so as not to affect the rest of others. This may make it inaudible ...

Published on 2006-04-15 20:58 â€¢ 213 times read

[Photo] 1.5V mini FM microphone

The microphone is as small as a finger, only 12 components are used, the working frequency is stable, and the ...

Posted at 2006-04-15 20:51 â€¢ 320 views

[Photo] 1.5V mini wireless FM microphone circuit diagram

1.5V mini wireless FM microphone circuit diagram: This article uses 12 components to do ...

Published on 2006-04-15 20:45 â€¢ 484 views

[Photo] 1.5V mini wireless FM microphone circuit diagram

var check_allow = "/d/Api/iscantalk.html"; var add_url = '/ d / article / write /'; function CheckLogin () {now_uid = ''; var ElecfansApi_checklogin = '/ webapi / passport / checklogin'; var logout_url = "{: U ('Login / logout')}"; var logout_url = 'http://bbs.elecfans.com/member.php?mod=logging&action=logout&refer=front'; $ .get (ElecfansApi_checklogin, function (data, textStatus) {if (data! = "") {EchoLoginInfo (data); CheckEmailInfo (data); data = $ .parseJSON (data); now_uid = data.uid; / * var login_content = 'write an article

'+ data.username +'

Quit '; * / var login_content =' write an article

'+ data.username +'

Set exit '; $ (' # login_area '). Html (login_content); var win_width = $ (window) .width (); if (win_width> 1000) {$ ("# mine"). MouseDelay (200) .hover (function () {$ ("# mymenu"). show ();}, function () {$ ("# mymenu"). hide ();});}} else {var content = 'Login Registration'; $ ('# login_area'). html (content); $ (". special-login"). click (function (e) {$ .tActivityLogin (); return false;});}});} $ (function () {// comment ------------------------------- var comment = $ ("# comment"); var comment_input = $ ("# comContent"); // Submit comment click event interaction $ ("# comSubmit2"). on ('click', function () {var content = comment_input.text (); // Empty input box comment_input. html (""). focus (); // Submit data to server $ .ajax ({url: '/plus/arcComment.php', data: {aid: $ ("# webID"). val (), dopost : 'apiPubComment', content: content}, type: 'post', dataType: 'json', success: function (data) {// Data format returned: if (data.status == "successed") {// Build temporary comment DOM var dom = ''; dom + = '

'; dom + =' '; dom + ='

'; dom + ='

'+ data.data.username +' '; dom + ='

'; dom + =' '+ content +' '; dom + =' '; dom + =' just now '; dom + =' '; dom + =' '; // insert a temporary comment to the list $ ("# comment ") .append (dom);} if (data.status ==" failed ") {// alert (data.msg); layer.msg (data.msg);}}}); return false;}); (function () {/ * * Insert single sign-on JS * / var setHost = 'https://passport.elecfans.com'; // Set domain name var script = document.createElement ('script'); script.type = 'text / javascript'; script.src = setHost + '/public/pc/js/t.passport.js'; script.setAttribute ("id", "sso_script"); script.setAttribute ("data-ssoSite", setHost); script.setAttribute ("data-ssoReferer", encodeURIComponent (location.href)); script.setAttribute ("data-ssoSiteid", "11"); var body = document.getElementsByTagName ("body"). item ( 0); body.appendChild (script);}) () / * * It is recommended to modify the style of the article without a picture * * / $ (". Article .thumb"). Each (function () {if ($ (this). find ('img'). attr ('src') == "") {$ (this) .find ('img'). remove (); $ (this) .parent (). css ('padding-left ',' 0px ');}}); / * Baidu share * / window._bd_share_config = {common: {bdText: '', // Custom share content bdDesc: '', // Custom share summary bdUrl: window.location.href, // Custom share URL address bdPic: ''} , share: [{"bdSize": 60, "bdCustomStyle": true}]} with (document) 0 [(getElementsByTagName ('head') [0] || body) .appendChild (createElement ('script')). src = 'http://bdimg.share.baidu.com/static/api/js/share.js?cdnversion=' + ~ (-new Date () / 36e5)]; var add_url = '/ d / article / write / '; // var check_allow = "{: U (' Api / iscantalk ')}"; var check_allow = "/ d / api / iscantalk"; var click_items_length = $ ('. art_click_count '). length; if ( click_items_length> 0) {var id_str = ''; $ ('. art_click_count'). each (function () {id_str + = $ (this) .attr ('data-id') + ',';}) // var url = "{: U ('Api / getclickbyids')}"; var url = "/ d / api / getclickbyids"; var id_data = 'id_str =' + id_str; $ .ajax ({url: url, data: id_data, type: 'post', dataType: 'json', success: function (re) {if (re.list.length> = 1) {var list = re.list; for (var i in list) {var t emp_id = list [i] ['id']; var temp_span = $ (". art_click_count [data-id =" + temp_id + "]") temp_span.html (list [i] ['click']);}} }})} $ ("# comContent"). click (function () {if (now_uid == '') {$ .tActivityLogin (); return false;}}) $ (function () {var follow_wrap = $ ( ".author-collect"); var now_uid = "{$ _super ['uid']}"; var face_src = "{$ _super ['uface']}"; var getFollowNum = $ (". followNum strong"). html (); // Follow $ (window) .on ('click', '.author-collect', function () {if (now_uid == '') {$ .tActivityLogin (); return false;} if ( $ (this) .attr ('id') == 'follow') {$ .post ('/ d / user / follow', {tuid: article_user_id}, function (data) {// Data format returned: if (data.status == "successed") {$ (". followNum strong"). html (++ getFollowNum); follow_wrap.html ('followed'). attr ('id', 'cancelFollow'). css ( 'background', '# 999'); var follow_user = ' '; $ (' # follow_list '). append (follow_user);} if (data.status == "failed") {alert (data.msg);}});} else {// Unfollow if ($ ( this) .attr ('id') == 'cancelFollow') {$ .post ('/ d / user / cancelFollow', {tuid: article_user_id}, function (data) {// Data format returned: if (data .status == "successed") {follow_wrap.html ('Follow'). attr ('id', 'follow'). css ('background', '# f90'); $ (". followNum strong"). html (-getFollowNum); $ ('# follow_list .face'). each (function () {var target_uid = $ (this) .attr ('data-uid'); if (target_uid == now_uid) {$ ( this) .remove ();}})} if (data.status == "failed") {alert (data.msg);}}); return false;}}});});}); / * var myface = "{$ _super ['uid'] | avatar}"; var myname = "{$ _super ['username']}"; var article_id = {$ article ['id']}; var article_user_id = {$ article ['mid']}; // Article author ID $ (function () {<notempty name = "clearnum"> // Reduce the number of reminders var count = parseInt ($ ("# noticeCount"). html ()); count = count-{$ clearnum}; $ ("# noticeCount"). html (count); if ( count

Telephone Speaker:

Telephone speaker is a kind of speaker unit which is used for multimedia devices. Telephone speakers have very clear voice sound.

Our main Multimedia Speakers are full ranges speakers units:

1) From the diameter: we have speakers in 1" ~ 3".

2) From the power output, we have speakers of 1W ~ 5W.

telephone speaker

FAQ

Q1. What is the MOQ?
XDEC: 2000pcs for one model.
Q2. What is the delivery lead time?
XDEC: 20 days for normal orders, 15 days for urgent orders.
Q3. What are the payment methods?
XDEC: T/T, PayPal, Western Union, Money Gram.
Q4. Can you offer samples for testing?
XDEC: Yes, we offer free samples.
Q5. How soon can you send samples?
XDEC: We can send samples in 3-5 days.

Telephone Speaker

Telephone Speaker,Paper Cone Speaker,Wireless Telephone Speaker,Phone Speakers

Shenzhen Xuanda Electronics Co., Ltd. , https://www.xdecspeaker.com