Bonjour,
Comment s'est passée ta journée (How was your day)? Hahaha.... Mine was awesome and just amazing... But I'm a lil tired with all the delayed work load......So many things to do, yet so little time left before due date. Okay, enough with the babbling.... :p
Let go straight to the point... Next week we will discuss on the LM35 circuit construction. So, now let's look at the relay switch circuit first.
Comment s'est passée ta journée (How was your day)? Hahaha.... Mine was awesome and just amazing... But I'm a lil tired with all the delayed work load......So many things to do, yet so little time left before due date. Okay, enough with the babbling.... :p
Let go straight to the point... Next week we will discuss on the LM35 circuit construction. So, now let's look at the relay switch circuit first.
Principle of Relay
- Electromagnet
- Armature that can be attracted by the electromagnet
- Spring
- Set of electrical contacts
Figure 1: Construction of Relay
In this Figure 1, you can see that a relay consists of two separate and completely independent circuits. The first is at the bottom and drives the electromagnet. In this circuit, a switch is controlling power to the electromagnet.
Operation of Relay
- When the switch is on, the electromagnet is on, and it attracts the armature (blue). The armature is acting as a switch in the second circuit.
- When the electromagnet is energized, the armature completes the second circuit and the light is on.
- When the electromagnet is not energized, the spring pulls the armature away and the circuit is not complete. In that case, the light is dark.
When you purchase relays, you generally have control over:
- The voltage and current that is needed to activate the armature
- The maximum voltage and current that can run through the armature and the armature contacts
- The number of armatures (generally one or two)
- The number of contacts for the armature (generally one or two -- the relay shown here has two, one of which is unused)
- Whether the contact (if only one contact is provided) is normally open (NO) or normally closed (NC)
Source taken from http://en.wikipedia.org/wiki/Relay
Source taken from http://electronics.howstuffworks.com/relay.htm
The relay that I am using consists of 3 pins, the change-over (com), normally-open (n/0) and normally-closed (n/c)
respectively. The relay is use for switching purposes to control the motor use in the Blood
Pressure circuit. So how to do the connections....It's very simple! First of all, we use an NPN transistor
(C547) where the base (B) is connected to the signal pin as below and
straight to
the PIC main board, Emitter (E) is connected to the ground and the
Collector (C) to the relay. Please refer Figure 2 for better understanding.
Figure 2: Schematic diagram of the relay switch circuit
Component you need to make the relay switch circuit are IN4007 diode, two 1kohm resistors, 1 LED,
1 NPN transistor and a relay, exactly as you can see in Figure 3.
Figure 3: Components used for the relay switch circuit
After designing the PCB layout on the PCB, I proceed with drilling holes on the PCB.
Next, I place the components accordingly by referring to Figure 2 schematic diagram and solder the components to the PCB neatly.
Figure 5: Soldering result
So this is how I place the components........ and It's done.........TADA....!
Figure 6: Component placement on the relay switch PCB board
Yeay...! We are done with the switching relay circuit. Therefore, next week we can begin to discuss on the LM35 as the temperature sensor circuit..... Wait for me k.....C ya.......... (o','o )v
Bubye peeps
XOXO
Bubye peeps
XOXO
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Quote of the day...!
He who is not courageous enough to take risks will accomplish nothing in life
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