Solid State Relay
Build a solid-state relay (SSR) using BT136 TRIAC. Controls AC loads without mechanical contacts, ideal for DIY electronics, automation, and hobby projects.
SSR circuit using TRIAC:
BT136 is a solid-state relay that can control AC loads without any noise. The BT136 TRIAC is a low-voltage DC input DC switch with low voltage and high reliability, fast and reliable operation.
DIY SSR for electronics:
The Solid State Relay (SSR) based on BT136 is an electrical switching device based on an AC load that does not use any mechanical connection. In contrast to mechanical relays, it makes use of a TRIAC (BT136) operated by a low-voltage DC control signal, which is silent, fast, and long-lasting to switch. It is a project that is suitable for hobbyists, students, and those who enjoy DIY electronics who seek reliable AC load control. The opto-isolator or resistor-diode triggering circuit is triggered by the input control voltage and switches the BT136 TRIAC ON or OFF, as performed by the AC load. SSRs can be used with lamps, small motors, heaters, and other AC appliances, providing better control and operational life than conventional relays. The design is focused on safety, effectiveness, and compactness, and it is ideal in an educational setup, home automation, or small-scale industrial applications.
⚡ Work & Installation (Input → Output):
- DC Control Input → Low-voltage DC triggers the SSR.
- Opto-isolator / Trigger Circuit → Activates BT136 gate safely.
- BT136 TRIAC → Switches AC load ON or OFF.
- AC Load → Lamps, motors, heaters, or other AC devices.
- Installation → Assemble components on PCB or breadboard. Connect AC load to TRIAC terminals, and DC control to gate circuit. Test SSR switching with low-voltage DC input.
Testing & Final Adjustments:
Connect the DC control input after assembly and make sure that the AC load switches ON and OFF. Check the gate triggering using a small current to make sure that it works. Be sure that the AC load and control circuit are isolated to avoid electric shock. Modulate the values of resistors and diodes in the triggering circuit to maximise the TRIAC switch. Test several AC loads to ensure the reliability of the SSR and note silent switching. Safe and consistent as well as efficient AC load control can only be guaranteed through proper testing, and thus, the BT136 solid-state relay is ideal in DIY electronics, home automation, and hobby applications.
Frequently Asked Questions - Solid State Relay:
What is BT136?
A TRIAC used for switching AC loads in solid state relay circuits.
Voltage requirement?
Control input typically 3–12V DC, AC load per TRIAC rating.
Can it switch high AC loads?
Yes, depending on BT136 current and voltage rating.
Silent operation?
Yes, SSRs have no mechanical contacts.
Applications?
Lamps, motors, heaters, home automation, DIY projects.
Beginner-friendly?
Yes, simple low-voltage control with AC isolation.
Do I need an opto-isolator?
Recommended for safe separation of AC and DC circuits.
PCB required?
Optional, can use breadboard for low-power prototypes.
Can it replace mechanical relay?
Yes, provides faster and longer-lasting AC switching.
AC load limitations?
Ensure load does not exceed TRIAC’s rated voltage/current.
Related Posts
Voltage Doubler Circuit
A voltage doubler circuit converts input voltage into nearly double using diodes and capacitors, ideal for electronics projects needing higher DC voltage.
Variable Power Supply using LM317
A variable power supply provides adjustable voltage output for electronics testing and DIY projects, allowing safe and precise control from 1.25V up to the input voltage limit.
fire alarm system wiring diagram
Learn how to wire a fire alarm system including detectors, control panel, sirens, and manual call points for reliable safety and early fire detection.
Transformerless Isolation Power Supply 12v Fix
Compact transformerless 12V fixed DC supply with isolation provides low-current power for small electronics safely using capacitor or resistive dropper techniques.
AC Motor Speed Controller
Build an AC 220V fan speed controller using a triac and a diac. Easy, efficient, and safe circuit for adjusting ceiling or table fan speed.
Convert 12v to 5v
Step down 12V to 5V using the LM317 adjustable voltage regulator. Ideal for powering 5V devices safely with a simple resistor setup.