modified 10 years ago

One wire control for up and down. Rev 1.5 - Question

02:23:18

****  can someone  give me a pointer about the noise injection and is there a way to stop it. ****
****  the noice injection  only seems to get into the pnp side not npn side ****

Track (one wirer control for up/down solanord's)
The lights on the top right side are the solanord's the left one is Down and the right one is Up. Up requires a pump and Down dose not, so the up light would control the solanord and the pump. Where the down light justs controls the solanord only.
The Leds below the lights are just a indercatter only, for visual only.
Buttons on the left side are as (top) is Down, the one below that is Up.
I have traced the one wirer (Colour blue)

published 10 years ago

2ctiby

10 years ago

There is a tiny amount of quiescent current / voltage in most circuits. Look at yours after the zenner...it says 436 nano amps. If you slide your finger from right to left on the oscilloscope repeatedly as far as it will go, then you will see what looks like that signal injection. Now slide from left to right as far as it will go and you will just see a stationary dot. In other words...take no notice of this, it is normal on EC. You can see a similar event in your other articles too if you look for them likewise.

DavidDeLaTorre

10 years ago

Thanks 2ctiby for the input..

2ctiby

10 years ago

You are welcome. Your circuit seems to work nicely with the buttons operating relay solenoids which you have temporarily replaced here with settings-adjusted lamps. The 2.5 amps at each relay may be as you require, but will those transistors be suitable to pass that high current?

DavidDeLaTorre

10 years ago

2ctiby, I'm using a tip122 NPN, 5 amps and 8 amps peaks. But you could change it to some thing that can do 25 amps.

DavidDeLaTorre

10 years ago

2ctiby, tip122 NPN Darlington Transistor.

DavidDeLaTorre

10 years ago

2ctiby, I have also got a diodes across the solanords to stop the back EMF, damaging the tip122 transistors.

2ctiby

10 years ago

Sounds good. Thanks for the info.

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