radio frequency transmitters plus the security of programmable card access for long-range access control with supported distances up to 200 feet away. The stand-alone unit is programmed using a built-in keypad and audio feedback so a computer is not required. Transmitters can be restricted based on time zones and/or gate location.

If you own multiple vehicles and need to carry the identification device with you, our portable "clicker" style transmitters can be utilized. Or if the same vehicle is used on a daily basis, you can utilize our "visor" style. Mounted on the overhead visor in the car, or the convenience of placing the transmitter on a key chain so it is always with you, the operation is simple and the information secure.

This is a precision ±15V regulator on a single side PCB.The circuit is based on EB-802 with design by zerosoft on www.headphoneamp.co.kr .I have replaced some components that easy to find in the market and design a new PCB that look like symmetry layout.But,you can replace the components with high quality component if you can find.

An op-amp with no feedback is already a differential amplifier, amplifying the voltage difference between the two inputs. However, its gain cannot be controlled, and it is generally too high to be of any practical use. So far, our application of negative feedback to op-amps has resulting in the practical loss of one of the inputs, the resulting amplifier only good for amplifying a single voltage signal input. With a little ingenuity, however, we can construct an op-amp circuit maintaining both voltage inputs, yet with a controlled gain set by external resistors.

When a relay is used to switch a large amount of electrical power through its contacts, it is designated by a special name: contactor. Contactors typically have multiple contacts, and those contacts are usually (but not always) normally-open, so that power to the load is shut off when the coil is de-energized. Perhaps the most common industrial use for contactors is the control of electric motors.

This is an electronic fuse that protects the load against short circuit. Relays must be chosen with a voltage value equals to the input voltage. Don't omit using the 100uF capacitor with appropriate voltage value with respect to the input voltage. If you can't provide, you can use C106 instead of BRX46.