好软件，我喜欢用他

pcad能仿真吗？

你这是什么软件画的图?

当电源电压没有波动的时候,应该看不到波形的,处于稳定状态,仿真是用multisim做的,k极频率时有时无,我也搞不清楚,不知是不是软件问题.

http://www.diodes.com/products/spicemodels/index.php在这里找找或许有

试试从protel转换，或者自己建

我用软件仿真了一下,事实上你说的有道理,但是并不是振荡状态,而是处于开关状态,用示波器看不到波形.[图片]500){this.resized=true;this.width=500;this.alt='这是一张缩略图，点击可放大。\n按住CTRL，滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}"onclick="if(!this.resized){returntrue;}else{window.open('http://u.dianyuan.com/bbs/u/27/1111763255.gif');}"onmousewheel="returnimgzoom(this);">

这是原本的模型,我看不出哪里错?#VERSION/component/pwm/acl/pwm_1/mc34063a.dec@@/main/1#DATEDWedJun912:05:25PDT1999#*********************************************************************#              ThistemplatecreatedbyAnalogy,Inc.              *#          forexclusiveusewiththeSaber(R)simulator.          *#  SaberisaregisteredtrademarkofAmericanAirlines,licensed  *#  toAnalogyInc.  Copyright1989-1999,AnalogyInc.              *#  Thistemplatemaynotbe  reproducedinanyway(physicallyor  *#  electronically)  withoutpermission  fromAnalogy,  Inc.  The  *#  content  ofthistemplateissubjecttochangewithoutnotice.  *#  Analogydoesnotassumeliabilityfortheuseofthistemplate  *#  ortheresultsobtainedfromusingit.                          *#*********************************************************************encryptedcomponenttemplatemc34063avccgnddrv_csw_csw_emctipk\inv_comp=ratings,rth_ja,rth_jc,rth_hs,part_type,part_class#########################USAGENOTESANDCAUTIONS#############################################################################################Ratingsinformationpwmtype..ratingsratings=    (tjmax=70,    tjmin=0,    pdmax_ja=1.25e+00,    pdmax_jc=3.00e+00,    vccmax=40,    vinmin=-0.3,    vinmax=40,    dvinmax=undef,    vin2max=undef,    voutmax=undef,    ioutmax=2.00e-01,    vformax=undef,    vformin=undef,    vpwrgnd=undef,    iformax=undef,    irefout=5.00e-02,    isoftmax=5.00e-02,    ieaout=5e-3,    isynout=5e-3,    ioscout=5e-3,    ioscchg=undef)number  rth_ja=100,        rth_jc=2,        rth_hs=undefstringpart_type="PWM"stringpart_class="VoltageMode"exportvalp  pwrdexportvaltctempjexternalnumbertemp,include_stress{#Manufacturerinformationpwm_info..mfr_infomfr_info=    (mfr_part_num="MC34063A",    libs=[dxocl],    config=single,    num_of_outputs=1,    pkg=pdip_8,    mfr=moto)#Manufacturerspecificationpwm_info..mfr_specsmfr_specs=    (freq_max=100e3,    tol_vref=2,    duty_max=95)