I need advice on how to connect a tachometer that can handle no more than 5v to a FP-TB-10 that is powered by 24v

[jason12381]

I'm using a
FP-1000 and a FP-TB-10.
The FP-1000 is powered by a 24v power supply.
I've connected a FP-AI-V5 to the FP-TB-10.
Now I have to connect a tachometer that requires power to the FP-TB-10. However, the tachometer cannot handle 24v. Should I use a power resistor to connect it to the FP-TB-10 or should i connect it to a completly separate power source?

Jason

[Aaron_G]

Jason,

Generally speaking, a separate 5 Volt power supply would be better than using a resistor divider network. A resistor divider network will usually be cheaper, but it it more vulnerable to voltage fluctuations, changing loads (e.g. the tachometer varying it's power consumption), and will consume power (in the resistors).

You could also build a small step-down voltage regulator from parts at Radio Shack, if memory serves correctly, you would need a LM7805 5VDC regulator, a 10 uF Capacitor, a 1 uF Tantalum Capacitor, a small printed circuit board, a small enclosure, some connectors and a heat-sink for the regulator. You could then feed the 24 Volts from your primary supply into the circuit and have your 5 Volt supply.

Regards,
Aaron