Aug 12, 2017 one of the serious problems in relay operated circuits is the relay. It is generally used to isolate high voltage circuit to low voltage circuit using a. Analyzing a transistor relay driver electrical engineering stack. Electro mechanical relay rating depend on your requirement of load. More interface options are available which includes popular uln2003. Therefore, a 9volt dc voltage source feeds the resistor. An electronic circuit will normally need a relay driver using a transistor circuit stage in order to converter its low power dc switching output into. How to build a relay driver circuit learning about electronics. In this project, we will go over how to build a relay driver circuit which is a circuit. If you connect the scope ground to the circuit ground, probe to the transistor collector, and turn the relay off you should see the transistor collector voltage rise to one diode drop above the 12v supply briefly then settle back to the supply voltage. One more thing one can do with an npn transistor is use it as a relay. Now a question arises, why do we need the extra bit of circuit to drive the relay. The coil of the relay needs a large current around 150ma to drive the relay, which an arduino cannot provide. This video pnp transistor based 12v dc relay control drive simple make it, this type transistor is a semiconductor device used to switch electronic signals and electrical power onoff control than.
In this project the npn transistor 2n2222 drives the relay when the npn junction gets saturated. Below is the circuit of a relay driver using the npn transistor bc 548. Transistor relay driver circuit circuit diagram, relay, transistors. Design a sustainable relay driving circuit using bjt. Transistor relay driver circuit with formula and calculations. However the low level signals from an electronic which may be derived from an ic stage or a low current transistor stage may be be pretty incapable of driving a relay directly. The relay is connected between the positive rail and the collector of the transistor. Pnptransistor based dc relay drive make triggering. Below is the dc relay driver circuit which we will build. Do you think that this is a suitable circuit using best practices. Following components are used in relay driver circuit using transistor. To suppress transients that may be caused by the relay opening and closing, we place a zener diode reverse biased in parallel with the relay.
Here is the information about relay driver circuit and different types of. Circuit design of 12v relay driver using transistor as a switch about this video. Types of relays and relay driver circuit buchholz relay. Its contact is closed when a current flows through a coil. The clamp, freewheeling or commutation diode provides a path for. In case of npn transistor as shown in fig when v1 is 0v or turn off then base current ib will not flow. How to make 12v relay driver circuit using transistor proteus. The relay which we use in this case is rated for 9v. A typical relay switch circuit has the coil driven by a npn transistor switch, tr1 as.