Laptops switched to battery power

Thunder and lightning are frequent in summer, and laptops powered by AC are prone to lightning strikes. For safety reasons, during thunderstorms, the computer has to be shut down frequently and the power plug unplugged. Frequent switching on and off is not only troublesome, but also shortens the life of the computer and may cause data loss.

If the computer is powered by a lead-acid battery, this problem can be easily solved.

Figure 1 shows the schematic diagram of a circuit powered by a battery.

The original alternating current power supply system of the machine has a rectified and stabilized output voltage of DC19V (3.15A); now it uses two 12V 20Ah maintenance-free batteries connected in series to form a 24V 20Ah battery E for power supply. A voltage stabilizing circuit as shown in Figure 1 must be added before it can be connected to the computer.

Principle: In Figure 1, the 24v voltage is added to the collector of Q1 through BX; the other voltage is stabilized by the voltage stabilizing circuit composed of R1, W1, D1, Q2 and Q1, so that Q2 and Q1 are turned on one after another, and from Q1 The emitter outputs a stable 19v (3.15A) voltage, which replaces the original AC regulated power supply and supplies power to the computer.

Among them, Q1 and Q2 are connected to form a Darlington tube; C1 is a filter capacitor, LED1 is a working indicator light, when the computer is working normally, LED1 emits light; V is a DC voltmeter with a range of only 50V.

When the circuit is working normally, the power consumption of Q1 is 16W. Therefore, add an aluminum heat sink of 10cmx10cmx0.3cm to the tube.

During use. Pay attention to the indication of voltmeter V. When the voltage drops to 21V, recharge E in time.