Circuits & Schematics - Supply - 5

Using the system shown in Fig. 1, you can quickly test a cable containing twisted-wire pairs and detect open or reversed pairs, shorted pairs, and shorts between unrelated pairs. The tester consists of an active test set that plugs into one end of ...

Let’s imagine that you need to add a power switch to something that’s battery-powered but processor-free; perhaps it must also be waterproof and thus membrane-sealed. Or perhaps you just want to use a shiny modern push-button rather ...

A high-side current-sense amplifier, IC 1 , offers a simple method of combining low-speed clocks or other signals with dc power in cables between subsystems (Figure 1). Designed for monitoring charge and discharge current in secondary batteries, IC ...

Latching relays change their states when you apply a short voltage pulse to their coils. Because these relays require no continuous coil currents to keep their states, you can save considerable power in the driver circuit. In one type of latching ...

In recent EDN design ideas, we’ve seen thermostat designs that meld the functions of sensor and heater into a single device: FET, BJT, or even a simple length of fine gauge copper wire. A virtue inherent in thermostat designs that use a ...

One option for driving high-brightness LEDs uses the standard stepdown buck converter (Figure 1). The sense resistor, R S , generates a feedback voltage, V FB , that sets the desired LED current, I LED , according to the equation Figure 1. A ...

Battery stack voltage monitor development ( Reference 1 ) is aided by a floating, variable potential battery simulator. This capability permits monitor accuracy verification over a wide range of battery voltage. The floating battery simulator is ...

The fuse described in this design idea does not drop the connection, it simply limits the output current. A behavior that is similar to a polyfuse, however the circuit shown in Figure 1 is more accurate, does not depend on ambient temperature ...

Editor’s note:Battery charging in a float or maintenance mode has been around for a while, especially for standby power, emergency lighting, telecom, uninterruptible power, and other critical power needs. The float method of charging is a ...

Included among the many applications for pulse-width modulation (PWM) are voltage regulation, power-level control, and fan-speed control. A PWM circuit for such systems can be implemented with three op amps on a single quad-op-amp chip (Fig. 1). ...