Dr Ronald Stiffler SEC technology

[erfandl]

All ---  Today, when I wanted to test the loop circuit, The circuit shown a certain behavior ! the LEDs it flashes with a regular rhythm ! I don't know whats happening ! also I hear a noise sound from the circuit with a regular rhythm like flashing LEDs. please see the below video and and tell your opinion.

https://youtu.be/KweXHfmq78w

thanks

[gyulasun]

Hi Erfandl,
I assume you checked the diode's wire is not touching the metal body of the clip, see attached picture where I mean.
Try to insert an Ampermeter into the battery wire going to the oscillator to see whether the LED flashings are accompanied by a change in input current.  If yes, then examine all the wire contacts plugged into the circuit board etc, look for bad contacts.
Worst case would be if the crystal inside would have started to develop a loose contact, if nothing else is found, use another crystal for the same oscillator to check it.   

Gyula

[erfandl]

Hi Erfandl,
I assume you checked the diode's wire is not touching the metal body of the clip, see attached picture where I mean.
Try to insert an Ampermeter into the battery wire going to the oscillator to see whether the LED flashings are accompanied by a change in input current.  If yes, then examine all the wire contacts plugged into the circuit board etc, look for bad contacts.
Worst case would be if the crystal inside would have started to develop a loose contact, if nothing else is found, use another crystal for the same oscillator to check it.   

Gyula

thanks Gyula. problem solved by reassemble the circuit

[Slider2732]

Am glad you fixed it..it looked to me like you'd done a Dr. Frankenstein on your circuit, it had come alive and was showing its heartbeat.
Sometimes i'm very glad to be wrong 

[mikrovolt]

So to me this means that the diodes do not introduce any time delay, its the L3 coil which injects the
signal in the loop that somehow produces this.

Just guessing,
From what is shown on the scope the diodes remain in conduction. I am not certain but I don't see the presence of any 4-6 nS delay from junction turn off.
Interestingly in the case of  L3 placement concentric to the loop there does appear to be lead lag as shown. The dynamics of the loop might be a circular wave guide
and the frequency drop might be the total reverse diode junction capacitance. Simlar to tuning miniature magnetic transmitting loop. Which makes me think that
a varicap or varactor insertion might show more effect on the frequency and some advantage possibly more interaction with the outer lattice having the original frequency.

Tnx, Joe