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Frequency Counter LS-223 ( Home brew )

[Outline] [Front view] [Inside view] [Block diagram]

Fig.1 Front view.

• Nixie tube display
• Countable up to 50MHz in TTL input
• Original case is also home brew.

• Manufactured From 1981( In my high school days ) to 1985
• Countable Frequency Range
  • 50Hz - 60MHz    ( TTL direct input )
  • 1MHz - 250MHz ( 1/10 Pre-scaled )

Fig2. Minimum coutable input signal level.

• Readout
  • 5 Nixie tubes

  Why nixie tubes were used ( out of date in mid '80s )?
  How to read frequency over 5 digits?

• Gate time
  • 1s,0.1s,10ms,1ms
• Master clock frequency
  • 10MHz
• Used semiconductors and tubes
  • 27 TTL , 1 ECL(Pre-scaler) , 1 IC(Regulator)

  1 FET , 10 Tr , 1 Diode , 5 Nixie tube , 6 LED