Circuits & Schematics

Rheostats Rheostats are simple and ubiquitous circuit elements, usually comprising a potentiometer connected as an adjustable two terminal resistor. The availability of manual pots with resistances spanning ohms to megohms makes the optimum choice ...

This design idea revisits another: “PWM power DAC incorporates an LM317” ( Ref. 1 ). Like the earlier circuit, this one implements a power DAC by integrating an LM317 positive regulator into a mostly passive PWM topology. It exploits ...

This design idea (DI) takes an unusual path to a power-handling DAC by merging an upside-down LM337 regulator with a simple (just one generic chip) PWM circuit to make a 20-V, 1-A current source. It’s suitable for magnet driving, battery ...

Toggle, slide, push-pull, push-push, tactile, rotary, etc. The list of available switch styles goes on and on (and off?). Naturally, as mechanical complexity goes up, so (generally) does price. Hence simpler generally translates to cheaper. Figure ...

The original application of the circuit in Figure 1 was to locate coins, but it applies wherever you need to locate metal objects. The circuit uses a beat-frequency technique: Whenever a metal object comes close to the search coil, the metal causes ...

Figure 1’s silly-simple voltage-to-time ADC is an exercise in dynamic range. Assuming that it is used with a 10-MHz counter/timer, its resolution is roughly 10 µV per count for inputs around 0 V and 100 mV per count at 1 kV, and it ...

Short-circuit protection is an obvious requirement for a power supply, especially when its load connects to a cable that's subject to damage. Many modern power-converter ICs include some means of protection, such as thermal shutdown, against ...

Figure 1 shows how to position a mechanical device into four discrete positions but with only two free outputs and one free input from the control system. The position depends on a set of cams and four corresponding limit switches. The 24V-dc motor ...

Figure 1 shows an example of on/off circuitry commonly used in battery-operated devices. The p-channel MOSFET, Q 1 , serves as a power switch. When you push the On button, S 1 , Q 1 ’s gate goes low. Q 1 turns on and supplies battery voltage ...