Hi,

I'm trying to reconstruct a multiplier circuit from a research paper related to a TENS unit. However i'm confused about the setup and connection from the power supply to the op-amp OP07 for the multiplier circuit and differentiator circuit. As i can see from the schematic the OP07 is connected to ground for both circuits in the plus and minus input, but from the block diagram i can tell that it should be connected to the power supply? How should i connect it? Specifically i am asking about the connection of fig. 5, OS1 and OS2.

The schematic is from the paper:
Sarkar, Jayjeet. (2015). Design and fabrication of A T.E.N.S. pain relief unit. 1-6. 10.1109/C3IT.2015.7060136.

 

However i'm confused about the setup and connection from the power supply to the op-amp OP07 for the multiplier circuit and differentiator circuit.

+12 volts connects to all +Vcc connections and -12 volts connects to all -Vcc connections. Is that clear?

 

I agree with ALEC in post #2. Those lines in the block diagram are flow paths, not actual connections. Quite a big difference. The secret code telling that is the arrow heads on those lines, telling us that it is a flow path.

 

What makes you think your multiplier will make 330 V. The numbers do not appear to properly compute. What diodes were you planning to use?

 

What makes you think your multiplier will make 330 V. The numbers do not appear to properly compute. What diodes were you planning to use?

Aside from the diode PRV issue, which is a valid concern, understand that there is no additional added POWER. so at an 18X multiplication there is also one eighteenth the current potentially available, at the theoretical best.

 

Aside from the diode PRV issue, which is a valid concern, understand that there is no additional added POWER. so at an 18X multiplication there is also one eighteenth the current potentially available, at the theoretical best.

I wasn't even thinking about power, rather the voltage losses at each stage of the multiplication. It will get worse if you try to draw even a small amount of power out of the other end.

 

+12 volts connects to all +Vcc connections and -12 volts connects to all -Vcc connections. Is that clear?

That makes sense, thanks.

 

What makes you think your multiplier will make 330 V. The numbers do not appear to properly compute. What diodes were you planning to use?

Thank you for pointing out the issue. I assumed since it was from a paper and his measurements showed 330V at the end of the multiplier circuit it was correct. But after doing a simulation i see it's no where near.

The diodes used should be 1N4007 according to the paper. However i'm planning on using another design after this.

Thanks again!

 

Aside from the diode PRV issue, which is a valid concern, understand that there is no additional added POWER. so at an 18X multiplication there is also one eighteenth the current potentially available, at the theoretical best.

Aside from the diode PRV issue, which is a valid concern, understand that there is no additional added POWER. so at an 18X multiplication there is also one eighteenth the current potentially available, at the theoretical best.

Thanks for pointing it out. The power is however not a concern as I only need to draw approx 20mA from the circuit. I will however use another circuit design with a transformer to get the correct voltage needed.

 

Probably the original author used a theoretical value for the 330 volts. And note that the value of R5, the resistor in series with the voltage, is not legible. And, with that circuit, the MJ10023, shunting the voltage is a bit unusual, at least as I see it.

 

Probably the original author used a theoretical value for the 330 volts. And note that the value of R5, the resistor in series with the voltage, is not legible. And, with that circuit, the MJ10023, shunting the voltage is a bit unusual, at least as I see it.

This is a constant problem in duplicating results from research papers: at least in my experience. There always seem to be details that are glossed over to the detriment of anyone trying to confirm or duplicate the results. This is why I have largely ignored the enormous volume of academic publishing in a career spanning half a century. N.B. this is a personal preference that I have had the luxury of indulging in. Many (most?) engineers may NOT have this luxury.

 

My impression has been that the verification of the validity of a new discovery was thru others being able to duplicate the results. thus publishing the means of getting the results accurately was the way to enhance one's reputation. I was once in the position of discovering the error on another's test process, which disproved his discovery of shock waves traveling at the speed of light in a solid. He was incorrectly measuring the speed of an electrical signal, not a shock wave, because of an incorrect connection.
From then on, all of my experiments included a brief reality check. Saved my credibility.

AND, HOW MUCH power CAN an OP07 op-amp ACTUALLY DELIVER???

 

My impression has been that the verification of the validity of a new discovery was thru others being able to duplicate the results. thus publishing the means of getting the results accurately was the way to enhance one's reputation. I was once in the position of discovering the error on another's test process, which disproved his discovery of shock waves traveling at the speed of light in a solid. He was incorrectly measuring the speed of an electrical signal, not a shock wave, because of an incorrect connection.
From then on, all of my experiments included a brief reality check. Saved my credibility.

AND, HOW MUCH power CAN an OP07 op-amp ACTUALLY DELIVER???

Only an insignificant amount.