Hi everyone, now I under designing the ESD sensor circuit.
so the circuit concept is when the ESD (8-30kV) event occurs, the ESD sensor circuit (away from ESD point around15cm) have to detect and send signal status to the MCU.
I already made and tested the circuit prototype but it not work
I doubt the antenna(make from normal wire) and tank circuit (LC) cannot receive electromagnetic or maybe from another causes?
Do you have any advice for this circuit? or Do you have other circuit to detect the ESD ?

Thank you!

 

hi Note,
I see that C3 is 100uF, that will absorb any weak signal the 1N4007 will pass through.
I would use a Germanium diode D1 for its low forward voltage, also use a very low cap value for C3.
Choosing C3 value may require a little empirical testing.
E
EDIT:
To increase the sensitivity.
I would also bias Q1 Base to approx 0.5V, ie just below the transistor conduction point.

 

hi Note,
I see that C3 is 100uF, that will absorb any weak signal the 1N4007 will pass through.
I would use a Germanium diode D1 for its low forward voltage, also use a very low cap value for C3.
Choosing C3 value may require a little empirical testing.
E
EDIT:
To increase the sensitivity.
I would also bias Q1 Base to approx 0.5V, ie just below the transistor conduction point.

Thank you for your advice

 

Further suggestions if you want to try this circuit:
• Use a strip of metal as the antenna -the wider the better but not so large that it picks up electrical noise that you don't want triggering your detector.
• Bias the transistor slightly on:

• Move C1 from across L1 to going from the bottom of L1 to ground.
• Provide feedback by putting five 1N914 diodes in series from the collector of the transistor (anode on collector) to where the new C1 connects to the bottom of L1.​

• Eliminate C2, D1, and R3 -connect the base of the transistor directly to where your "antenna" connects to L1.
• Eliminate R2 because it would interfere with the bias of the transistor.
• Consider removing the TVS, at least until you get the circuit working.Most likely it will not be needed.
• Change C3 to 470 pf and connect from collector to ground (no cap desired on base).
• Use an 2N3904, 2N4401, KSP10, or MPSH-34 or similar for the transistor. The last two are better choices because they faster.
• Change R1 to (about) 39k .

I have used the circuit as modified above in may electric impulse detection applications and even some turned radio receivers and strongly suspect that it can work in your application.


If your signal is not sufficient you can use an LM358 to add gain and square up the signal if necessary. R1 is not installed.

 

Your LC tank resonates at 5kHz. I doubt that is anywhere close to where majority of energy in an electrostatic discharge is.

 

Your LC tank resonates at 5kHz. I doubt that is anywhere close to where majority of energy in an electrostatic discharge is.

Hi kubeek,
How to choose the frequency of LC?
I have to follow frequency of ESD or not?
For the example, If frequency of ESD equal 17MHz (1/60ns), I have to create LC that frequency equal 17MHz or not ?

 

Yes, somewhere around 17MHz would be probably be a good start. Even higher should work as well, since the initial peak has rise time of 1ns