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Old 4th Sep 2010, 7:32 pm   #1
deco-doctor
Tetrode
 
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Join Date: Mar 2006
Location: Brackley, Northants. UK.
Posts: 53
Default Homebrew valve curve tracer.

Hi All

I have just finished my homebrew valve curve tracer. I thought there maybe some folks here that might be interested.

The curve tracer is based on a small ready made PCB module with a pre-programmed microprocessor and some software that runs on a Windows PC connected by an RS232 link.

The completed project has set of various valve sockets, a valve socket pin switching system that uses the same switch settings as an AVO valve tester, a power supply with the HT voltage controlled via a variac, a regulated screen supply, and an adjustable AC heater supply.

Small signal triodes and power valves requiring up to 100mA anode current can be traced. The characteristic curves, the plate resistance, the mutual conductance, the Mu and the reference anode current and voltage at 0 grid volts of the valve under test are all displayed on the PC. I have also included a switch to quickly swap between each half of a double triode.

I have attached some pictures and an example of the results screen when tracing a 7193 (2C22) single triode.

Martin
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