Class A amplification of large signals

bertus

Joined Apr 5, 2008
20,085
Hello,

What happens when you put a resistor of 10 Ohm between the TTLport and R2.
This for impedance matching.

Greetings,
Bertus
 

bertus

Joined Apr 5, 2008
20,085
Hello,

I overlloked something.
A TTL port can not handle a sinewave signal.
Use a analog gate like a 4066 instead.

Greetings,
Bertus
 

Thread Starter

Peter Pan

Joined Mar 24, 2005
122
Hello,

I overlloked something.
A TTL port can not handle a sinewave signal.
Use a analog gate like a 4066 instead.

Greetings,
Bertus
Okay, thank you, I'll try it (my gate actually outputs DC+sinewave as on pic).

What zener diode would you recommend? (In simulation I did not specify particular device and used generic zener).
 

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bertus

Joined Apr 5, 2008
20,085
Hello,

When you look at the original drawing it are 15 Volts zeners.
The one for gate regulation is 3.3 Volts.



Greetings,
Bertus
 

bertus

Joined Apr 5, 2008
20,085
Hello,

The zeners are placed there to protect the gate of the FET.
I have attached a datasheet of the IRF840, to show its capabilities.

Greetings,
Bertus
 

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Thread Starter

Peter Pan

Joined Mar 24, 2005
122
Hello,

The zeners are placed there to protect the gate of the FET.
I have attached a datasheet of the IRF840, to show its capabilities.

Greetings,
Bertus
Thank you very much!

I cannot find spice model of 4066 in Web and just wonder whether you (or other forum members) have it.
 

bertus

Joined Apr 5, 2008
20,085
Hello,

An other alternative is a pin diode switch.
In this application note is described how it works.

Greetings,
Bertus
 

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italo

Joined Nov 20, 2005
205
Are you sure that amplification is required as opposed to level shifting to 50-60v. You will defenetly need that volts source to acconplish this. there are some dif. amplifier in the voltage range.
 

Thread Starter

Peter Pan

Joined Mar 24, 2005
122
Are you sure that amplification is required as opposed to level shifting to 50-60v. You will defenetly need that volts source to acconplish this. there are some dif. amplifier in the voltage range.
It can be seen in the pictures of input and output attached that input has DC component about 6V and AC component less than 1V but output has zero DC component and about 50-60V AC. So output is not just input shifted by some 50-60 V.
 

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