Dual Relay Driver Board Circuit Schematic

A simple and convenient way to interface 2 relays for switching application in your project. This relay driver boosts the input impedance with a regular BC547 NPN transistor (or equivalent). Very common driver. It can drive a variety of relays, including a reed-relay. Transistor Q1and Q2 are a simple common-emitter amplifier that increases the effective sensitivity of the 12 volt relay coil about a 100 times, or in other words, the current gain for this circuit is 100. Using this setup reduces the relay sensitivity to a few volts. R3 and R4 restricts the input current to Q1 and Q2 to a safe limit. Diodes D3 and D4 are EMF dampers and filter off any sparking when the relay
de-energizes.

---

Picture of the project:

Front View Of Dual Channel Relay Board Driver

---

Circuit diagram:

2 Channel Relay Driver Circuit Diagram

---

Parts:

R1-R2 = 1K
R3-R4 = 5.6K
C1-C2 = 100nF-63V
D1-D2 = Red LED
D3-D4 = 1N4001
L1-L2 = 12V Relay
Q1-Q2 = BC547

Specification:

• Input - 12 VDC @ 84 mA
• Output - two SPDT relay
• Relay specification - 5 A @ 230 VAC
• Trigger level-2~5VDC
• Berg pins for connecting power and trigger voltage
• LED on each channel indicates relay status

Subscribe now and get all Projects, Circuit Diagrams and EBooks right in your inbox absolutely free. Don't worry it takes only 20 seconds.

be a part of us join 5000+ subscribers

Related Projects:

PCB for 20W Stereo Amplifier is Available Now. Click Here for Details.