Circuits & Schematics - 10

The exposure tester in this Design Idea measures the on time of a light source, whether an LED, an incandescent lamp, a halogen lamp, or another source. It can be made with an ordinary stopwatch and a few simple components (figures 1 and 2). An ...

It is common practice to power a MOSFET with a comparator and with an unregulated voltage and to power the comparator driving it from a regulated one (Figure 1). Many loads are insensitive to driving voltage, so it would be a waste of money and ...

Recently I published a simple platinum resistance temperature detector (PRTD) design idea ( Reference 1 ) that was largely inspired by a deviously clever earlier DI by Nick Cornford ( Reference 2 ). Remarkable and consistently constructive critical ...

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 ...

Frequent contributor Nick Cornford recently published a delightfully clever design idea ( Reference 1 ) using a platinum RTD calibrated to output a 1 mV/ C signal that’s perfect for direct readout via a standard DMM I thought Nick’s ...

Way back in 1986, famed analog innovator Jim Williams, in “Designs for High Performance Voltage-to-Frequency Converters” ( Reference 1 ) published his “King Kong” 100 MHz VFC. I have never seen its equal. Certainly Figure ...

Before shipping moving-coil meters, manufacturers may short-circuit the meters' terminals with a length of wire, which provides effective electromagnetic damping and results in better immunity to external mechanical vibration and shocks that ...

There are several applications at home or industry for long delay timers (ON or OFF delay). Time delays on the order of seconds can be generated using 555 timer circuits, provided the timing capacitor values do not exceed the limit specified by 555 ...

Psychologists tell us that frustration increases drive. I was driven to produce the circuit in this design idea by my increasing frustration with a collection of digital thermometers, all of which claimed accuracy to within 0.1 C but the readings ...

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 ...