Whats wrong?

Thread Starter

Wind23

Joined Sep 26, 2012
22
I am working on this circuit and i am having problem with the relay whereby it does not switch nicely and seems to make weird noise as if it got stucked.

Here is the circuit. http://www.zen22142.zen.co.uk/ronj/rt5.html

Can anyone help me please? The relay is a 12vdc relay and i gave 13V as power supply.
The 13V is sourced from a car battery and another weird thing i found out recently is the weird noise sometimes happens when i am testing it with a low current 12v solar panel but does not happen when connected to car battery. Why does this happens? Does it mean it only operates at low current and not at high current? Pls help.
 

crutschow

Joined Mar 14, 2008
34,285
If the voltage from the solar panel to the relay coil is actually less than 12V, then that may cause the relay to chatter. What current is going through the relay contacts?
 

Thread Starter

Wind23

Joined Sep 26, 2012
22
If the voltage from the solar panel to the relay coil is actually less than 12V, then that may cause the relay to chatter. What current is going through the relay contacts?
Hi, if connected to the car battery @ around 13v, the relay gets around 13V and the relay does not make clicking sounds whereas if connected to the solar panel(Voltage change as sunlight increases n decreases), the clicking sound of relay is heard.

I think it has nothing to do with supply voltage as a 12v relay can work with 13V or lower but the current from the car battery might be higher so causing the problem. Please correct me if i am wrong.

Thanks.
 

#12

Joined Nov 30, 2010
18,224
You have it exactly backwards. A car battery is a very strong source of current. Having plenty of current makes it work right. Clicking is not working "right".
 

Thread Starter

Wind23

Joined Sep 26, 2012
22
You have it exactly backwards. A car battery is a very strong source of current. Having plenty of current makes it work right. Clicking is not working "right".
Ok. Another weird thing i see is the relay clicking sound appeared immediately when i connect it to the small solar panel with the thermistor heated under the sun but when i connect it to car battery with the thermistor under the sun, no clicking sound but relay does not switch and i assume its because its not hot enough. The circuit only works under very hot conditions i supposed.
 

Thread Starter

Wind23

Joined Sep 26, 2012
22
Hi there is a pot in the circuit given n i m following that. I m wondering if i need to change the pot and series resistor values as the system reacts very slow. As mentioned earlier when connected to car battery there were no clicking sounds n i assume its working well but it took a long time to turn on the load that i wish to run after the relay shifts .
 

Thread Starter

Wind23

Joined Sep 26, 2012
22
For the time control i m not using the 2 pots tat were connected with the 100k resistors. Just connect 100k resistors with the diodes.
 

Thread Starter

Wind23

Joined Sep 26, 2012
22
Can anyone tell me how to solve this problem please ? How do i do on-circuit testing of the components soldered on pcb?
 

shortbus

Joined Sep 30, 2009
10,045
For the time control i m not using the 2 pots tat were connected with the 100k resistors. Just connect 100k resistors with the diodes.
How can you expect to make random changes in a circuit and have it work?
Things that are in the circuit schematic are there for a reason.
 
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