Circuits & Schematics - 20

In the proximity detector of Figure 1, a 4-in.-sq piece of copper-plated pc board serves as an antenna that forms one plate of a capacitor. An approaching (grounded) person serves as the other plate, producing a capacitance value of 2 to 5 pF that ...

Introduction A 500 V protection circuit for low voltage high impedance measuring instruments is shown in Figure 1. The protection is accomplished by limiting the amount of current going into the measuring instrument. The circuit will protect ...

Recently, I’ve been working on a solar off-grid monitoring system. In the system are a few split-core Hall effect sensors to monitor DC current in the solar panel current, the battery charge current, and the inverter input current. These ...

Lighting LEDs from a single 1.5 V cell poses a problem because their forward voltages are higher than the cell’s. The simplest way to light the LED is to use a step-up dc/dc converter. This Design Idea offers a simple and reliable alternative ...

Figure 1. Common view of the Precision Thermocouple Amplifier board. This precision thermocouple sensor module performs cold-junction compensation and digitizes the signal from any type of thermocouple. The output data is formatted in degrees ...

The standard boost converter in Figure 1 uses not only IC 1 , C 1 , L 1 , D 1 , and C 2 to generate a main 5 V output, but also additional small, low-cost components to provide two auxiliary supply rails of 10 and 5 V. These auxiliary outputs are ...

Many electronic-control systems have digital outputs that use transistors. One method of improving the security in these outputs is to use an oscillating signal to represent a logic-high state instead of a fixed voltage level (Figure 1). This type ...

A rechargeable battery’s load should be disconnected at the point of complete discharge, to avoid a further (deep) discharge that can shorten its life or destroy it. Because a battery’s terminal voltage recovers when you disconnect the ...

It is sometimes necessary for a microcontroller to generate a pulse whose voltage is higher than the power-supply voltage of the microcontroller. The circuit in Figure 1 allows you to generate 14 V pulses from a 5 V power supply. An adaptation of ...

Mechanical push-pushbutton switches (also known as alternate-action or push-on/push-off switches) can be bulky and expensive. As an alternative, an electronic version uses a cheaper, NO (normally open), momentary-on switch (Figure 1). Figure 1. ...