Maximum Minimum Voltage Indicator

This circuit indicates which of three voltages in the range from about about -4V to about +4V – at A, B and C – is the highest by lighting one of three indicator LEDs. Alternatively, it can be wired to indicate the lowest of three voltages or to indicate both the highest and lowest voltages. […]

Mains Pulser

The pulser is intended to switch the mains voltage on and off at intervals between just under a second and up to 10 minutes. This is useful, for instance, when a mains-operated equipment is to be tested for long periods, or for periodic switching of machinery. Transformer Tr1, the bridge rectifier , and regulator IC1 […]

Negative Auxiliary Voltage

Some circuits need a negative supply voltage that only has to supply a small current. Providing a separate transformer winding for this (possibly even with a rectifier and filter capacitor) would be a rather extravagant solution. It can also be done using a few gates and several passive components. The combination of gate IC1a and […]

DMM Fuse Protector

Typically the input protection fuse of your DMM will blow in the middle of a demonstration or an exciting phase of your construction work. Spare fuses are always hard to find, and if available take a lot of time to install. This circuit replaces the fuse by a 500 mA current limiter. When resistor R1 […]

Adjustable Zener Diode

A Zener diode is the simplest known type of voltage limiter (Figure 1) As soon as the voltage exceeds the rated voltage of the Zener diode, a current can flow through the diode to limit the voltage. This is exactly the right answer for many protection circuit applications. However, if it is necessary to limit […]

Low-Voltage Cutout For 12V SLA Batteries

This simple circuit protects an SLA battery from over-discharge by disconnecting the load when the terminal voltage drops below a preset level. In operation, a sample of the battery voltage is derived from the 22kΩ resistor and 20kΩ trimpot divider. This is applied to the non-inverting input (pin 3) of IC1, where it is compared […]

Stable Zener Reference

Nowadays some first-rate voltage references are available. Take the LM385 for example: this is available for different voltages and even comes in an adjustable version. What is more, the current consumption may be kept very small (10 µA). But as often happens, you may not have one to hand when you need one for an […]

4-Line Bus Port Protection Array

4-Line Bus Port Protection Array Vishay Intertechnology, Inc. released a new 4-line ESD – protection array in the new ultra-compact LLP2510 package. Featuring a compact 2.5 mm by 1.0 mm footprint and ultra-low profile of 0.55 mm, the VBUS54ED-FBL offers low capacitance and leakage current for the protection of high-speed data lines against transient voltage […]

Fast Response Voltage Comparator

Fast Response Voltage Comparator STMicroelectronics , a global semiconductor leader serving customers across the spectrum of electronics applications and a leading manufacturer of standard ICs, today introduced a high-speed voltage comparator with the market’s best ratio of current consumption to response time. ST’s high-speed voltage comparator addresses applications where fast response time is critical, such […]

Extended Voltage Range FRAM

Extended Voltage Range FRAM Fujitsu Semiconductor Europe introduces a new FRAM (Ferroelectric Random Access Memory) product series with an extended voltage range of 3.0V – 5.5V, offering significantly greater design flexibility for customers in the industrial and metering sectors. With this product series, Fujitsu not only supports 3V systems, but 5V systems as well. The […]