VCO range 100KHz to 200KHz

[ceaser]

vco 100khz

hi all

now i'm trying to desine a VCO has a range between 100KHz to 200KHz.

i tried to use the wien bridge osc.

but it gives me max freq of 20KHz because it use op-amp.

similarly 555 chip because it has two op-amp's in its two inputs.

i shouldn't use any freq dividers or multipliers.

just VCO sweeps from 100KHz to 200KHz.

can any one help me!

 

[IanP]

op amp vco 100khz

To design VCO operating in this range you can use part of the CD4046 ..
https://www.electronics-tutorials.com/devices/74hc4046.htm
A control voltage can be connected to pin 9, and output signal can be taken from pin 4 (see picture below) ..

The exact range and component values (R1, R2 and Cx) can be determined by extensive charts included in the above data sheet ..

Regards,
IanP

 

[ceaser]

chemelec cd4046

thx alot IanP

Added after 4 hours 43 minutes:

Sorry guys

but now my instractor said

"no use of any chips you can use colbet or hartly tuned circuits "

but the problem of these circuits is the coil

we need coil of 70 mH

because the varying capasitors in the market are between 10&40 PF

so if there is no way to design this VCO without chips or op-amp's

i will make coil with large inductance

so any one know how to calculate the inductance using iron core

what i know is the inductance is a function of

No of turns,wire length,............etc

 

[Guest]

hi


try this

**broken link removed** or this
http://www.ee.surrey.ac.uk/Workshop/advice/coils/

Best Regards
Pendragon

 

[IanP]

Use the AL value (from powdered iron core data sheet) and the formula(s) below to calculate the number of turns for a specific inductance.
Where:
N = Number of turns, L= inductance (µh), AL = inductance index ((µh) / 100 turns)
https://www.bytemark.com/products/ipcores.htm

Regards,
IanP

 

[ahmad_abdulghany]

Assalamo alaykom,
How are you
If you want to know many things, concepts, circuits, ....etc. about discrete components oscillators, then you can check this link: https://www.electronics-tutorials.com/oscillators/oscillator-basics.htm In shaa allaah, you will find it very useful,
Rabbena ma3aak,
Ahmad,

 

[mircea]

why don't you try:

**broken link removed**
**broken link removed**
**broken link removed**

rgds,
M