Duty Cycle Converter

On AC-CDI v7.9 or DC-CDI v2.1 the tacho output available at RB5/PIN11/TP1 can drive a tachometer.
The signal is a +5volts level and 5% Duty Cycle signal:

but some tachometers need a +12v level at 50% DC signal !

In order to work with such tachometers I create a small microprocessor able to convert the Duty Cycle while keeping the same frequency.

It is available in the SHOP section.

Characteristics

Min

Typ

Max

Unit
Output Duty Cycle

50

%
Input Duty Cycle

0.1

50

%
Input Voltage

2.5

5

V
Output Voltage

5

V
Frequency

5

800

Hz
RPM

30

48,000

RPM

Working:
The processor convert the signal to an even 50% ratio.
A +5v level 50% DutyCycle is available at pin2, then a NPN transistor raise the signal to a +12v level.

8Hz:

800Hz:

Schematics:

Wiring:

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