Sign in

Not a member? | Forgot your Password?

Search Sci.Electronics.Design

Search tips

Recent Blogs on Electronics-Related

Two Capacitors Are Better Than One
posted by Jason Sachs


Voltage Drops Are Falling on My Head: Operating Points, Linearization, Temperature Coefficients, and Thermal Runaway
posted by Jason Sachs


Optimizing Optoisolators, and Other Stories of Making Do With Less
posted by Jason Sachs


Someday We’ll Find It, The Kelvin Connection
posted by Jason Sachs


10 Items of Test Equipment You Should Know
posted by Jason Sachs


First-Order Systems: The Happy Family
posted by Jason Sachs


Lost Secrets of the H-Bridge, Part IV: DC Link Decoupling and Why Electrolytic Capacitors Are Not Enough
posted by Jason Sachs


April is Oscilloscope Month: In Which We Discover Agilent Offers Us a Happy Deal and a Sad Name
posted by Jason Sachs


Specifying the Maximum Amplifier Noise When Driving an ADC
posted by Rick Lyons


BGA and QFP at Home 1 - A Practical Guide.
posted by Victor Yurkovsky


3 LEDs powered by fingers - puzzle
posted by Henryk Gasperowicz


Series circuit - 3 LEDs
posted by Henryk Gasperowicz


Video: The PN Junction. How Diodes Work?
posted by Stephane Boucher


Two jobs
posted by Stephane Boucher


2N3055 | 8051 | Amplifier | AVR | Battery | Capacitors | Charger | CMOS | Converter | DAC | Decoder | Demodulator | Diode | Ethernet | Flash | FPGA | GPS | I2C | IDE | Laser | LCD | LED | LTSpice | MOSFET | Op-amp | Oscillator | Oscilloscope | PCB | PID | PLL | PSpice | PSU | PWM | RFID | RS232 | RS485 | SMPS | Solenoid | Spice | Switcher | TCP/IP | Transformer | Transistor | TTL | USB | VCO | Zener

See Also

DSPEmbedded SystemsFPGA

design | Whats different between these two circuits?


There are 5 messages in this thread.

You are currently looking at messages 1 to 5.

Whats different between these two circuits? - readeraz - 2008-07-23 19:04:00

Ringing choke circuit and blocking oscillator are different names of
oscillator.
Are they same meaning or they are different circuit in practice?
How to distinctly identify  them?
thanks

Re: Whats different between these two circuits? - Tim Williams - 2008-07-23 20:49:00

Blocking oscillator blocks, LC oscillator rings.  Pretty clear on the scope.

The interesting ones are where you have both. . .

Tim

-- 
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

"readeraz" <c...@126.com> wrote in message 
news:a...@i24g2000prf.googlegroups.com...
> Ringing choke circuit and blocking oscillator are different names of
> oscillator.
> Are they same meaning or they are different circuit in practice?
> How to distinctly identify  them?
> thanks 



Re: Whats different between these two circuits? - Don Klipstein - 2008-07-23 21:13:00

In <a...@i24g2000prf.googlegroups.com>, 
readeraz wrote:

>Ringing choke circuit and blocking oscillator are different names of
>oscillator.
>Are they same meaning or they are different circuit in practice?
>How to distinctly identify  them?

  Both resemble variants of the Hartley oscillator, with the capacitor 
across the tapped inductor removed.

  A blocking oscillator has the oscillation feedback path through a 
resistor and capacitor in parallel.  During the half-cycle where the 
transistor conducts, positive feedbck is through the capacitor.  Once the 
capacitor has become excessively charged to maintain enough feedback to 
keep the transistor saturated, this half-cycle ends.  This half-cycle is 
usually the shorter one.  During the other half-cycle, the transistor is 
off until the capacitor is discharged sufficiently by its paralleled 
resistor to allow current to flow through the base of the transistor.

  In a ringing choke oscillator, the oscillation feedback (assuming a 
bipolar transistor) is through a resistor.  The "transistor-on" half cycle 
is usually the longer one.  That half-cycle ends when either the tapped 
inductor saturates or the transistor comes out of saturation.  The 
transistor-off half cycle's onset reinforces itself with the feedback 
winding's voltage changing in a direction to reduce the transistor's 
collector current.  In fact, once collector current starts decreasing, the 
transistor usually quickly slams off, and a high voltage pulse can occur.
  If a ringing choke oscillator is not carefully designed, the transistor 
may be destroyed by breakdown from high voltage pulses resulting from 
suddenly interrupting current flowing through the inductor.
  The transistor-off half cycle ends when the transistor's collector 
current has decreased to zero and has become steadily zero.  There may be 
a delay for stray capacitance charged by the high voltage pulse to 
discharge before the feedback winding produces voltage in the forward bias 
direction, but that is usually short.

 - Don Klipstein (d...@misty.com)

Re: Whats different between these two circuits? - readeraz - 2008-07-30 22:27:00

On Jul 24, 9:13 am, d...@manx.misty.com (Don Klipstein) wrote:
> In <a231f34f-d2dd-4f2c-a7f0-9c2c45e59...@i24g2000prf.googlegroups.com>,
>
> readeraz wrote:
> >Ringing choke circuit and blocking oscillator are different names of
> >oscillator.
> >Are they same meaning or they are different circuit in practice?
> >How to distinctly identify  them?
>
>   Both resemble variants of the Hartley oscillator, with the capacitor
> across the tapped inductor removed.
>
>   A blocking oscillator has the oscillation feedback path through a
> resistor and capacitor in parallel.  During the half-cycle where the
> transistor conducts, positive feedbck is through the capacitor.  Once the
> capacitor has become excessively charged to maintain enough feedback to
> keep the transistor saturated, this half-cycle ends.  This half-cycle is
> usually the shorter one.  During the other half-cycle, the transistor is
> off until the capacitor is discharged sufficiently by its paralleled
> resistor to allow current to flow through the base of the transistor.
>
>   In a ringing choke oscillator, the oscillation feedback (assuming a
> bipolar transistor) is through a resistor.  The "transistor-on" half cycle
> is usually the longer one.  That half-cycle ends when either the tapped
> inductor saturates or the transistor comes out of saturation.  The
> transistor-off half cycle's onset reinforces itself with the feedback
> winding's voltage changing in a direction to reduce the transistor's
> collector current.  In fact, once collector current starts decreasing, the
> transistor usually quickly slams off, and a high voltage pulse can occur.
>   If a ringing choke oscillator is not carefully designed, the transistor
> may be destroyed by breakdown from high voltage pulses resulting from
> suddenly interrupting current flowing through the inductor.
>   The transistor-off half cycle ends when the transistor's collector
> current has decreased to zero and has become steadily zero.  There may be
> a delay for stray capacitance charged by the high voltage pulse to
> discharge before the feedback winding produces voltage in the forward bias
> direction, but that is usually short.
>
>  - Don Klipstein (d...@misty.com)

Thank you very much for your explain.

Re: Whats different between these two circuits? - readeraz - 2008-07-30 23:48:00

most of the rcc is working as negtive action so that when the
trnsistor shut off, the energy is transported to load at second
winding. and this avoid super higher voltage apply on the transistor.

When the transistor become turen on from off, more circuit uses a
capactor as an accelerator to force trnasistor on speedly. thats why I
pulzzed their difference.

That seems there is no too distinct between them.

Hoever, thank you very much for your wonderful explain.



On Jul 24, 9:13 am, d...@manx.misty.com (Don Klipstein) wrote:
> In <a231f34f-d2dd-4f2c-a7f0-9c2c45e59...@i24g2000prf.googlegroups.com>,

>   Both resemble variants of the Hartley oscillator, with the capacitor
> across the tapped inductor removed.
>
>   A blocking oscillator has the oscillation feedback path through a
> resistor and capacitor in parallel.  During the half-cycle where the
> transistor conducts, positive feedbck is through the capacitor.  Once the
> capacitor has become excessively charged to maintain enough