Tiger28760
Member
I know this seems dumb but I’m having trouble sourcing a 5K pull up resistor for use in the ESP Inhibit circuit. Can someone please point me in the right direction to buy one?
Thanks!
Thanks!
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5K Pull Up Resistor
- Thread starter Tiger28760
- Start date
Halleffect
Active Member
Seems like a typo to me… how could a 5K resistor need to be 3 W given P = V squared over R, 14.4 * 14.4 / 5,000 = .041… 1/8 W will work, or 1/4 W, or 1/2 W, and I don’t understand 1% tolerance is required, or that it’s not 5K or 4.7K or 5.1K
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I agree, especially for a 'pull up' resistor function, a 1% tolerance is way overkill. For "5K" use the much more common "4.7K". And, as quoted above., in a 14 volt airplane the power consumption can't exceed about 200/R watts (R in ohms).
ariel_arielly
Active Member
Hi. You can use either 4.99kOhms or 5.11kOhms 1% 1/4W resistor. You can buy it in every electronic components shop.
Walt
Well Known Member
Why do you need an inhibit switch? A simple tap on the AP bar you can turn on/off.
georgemohr
Well Known Member
I (possibly incorrectly) don't understand the need for this switch anyway. I have an AP Master switch that depowers the servos, and I'm pretty certain everyone else has this in their design as well.
-135Driver
Member
The ESP inhibit switch allows you to turn that function off without turning the whole autopilot system off so you can go do aerobatics and not have the system try to engage the autopilot during the maneuver. And with the autopilot system still on, you can quickly engage it if necessary.
Walt
Well Known Member
You can turn ESP on/off with a tap on the AP bar and a tap of the ESP button, has nothing to do with regular functions of the AP.
Attachments
Not everyone. I instruct in the local flying club’s 182, with 3 mini G-275 efis controlling the autopilot. No AP on/off switch, it boots up with ESP on. When I ask for a steep turn, or a stall, most pilots look perplexed, not understanding that the ESP is fighting them. To turn it off you have to go down one layer, then sideways, in the 275’s display. I usually pull the AP CB, it’s easier.
-135Driver
Member
Agreed…multiple ways to do the same thing.
Walt
Well Known Member
I alway try to use the KISS approach, avoiding unnecessary switches/wiring whenever possible.
You only need a pullup resistor if using the analog GP inputs on the GEA 24. The ESP disable can also be assigned to any of the discrete inputs in the GEA 24 or GAD 27 and you don't need a pullup resistor for the discrete inputs. The only exception is Discrete 8 and Discrete 9 on the GAD 27, those are internally pulled down apparently as I discovered. But if you use one of the discrete inputs, you only need to provide a switch to ground.
Mine is wired that way into a discrete with a disable switch on the panel.
