Device detect the presence of DC voltage in the range from 6 to 15 and In check condition of electrical circuits with resistance to 10 ohms. Both operations are performed using only two of the probe, without any switching.
Battery GB1 (see diagram) connected in series with two parallel-connected the readout circuits. One of them (the resistor R1 and led HL1) - indicator voltage, the second indicator safe circuits (resistor R2 and the led HL2). When check the voltage in the electrical circuit of the vehicle light led HL1 and at the same time recharging the batteries. When checking the integrity of the a circuit, if the resistance is small or it is closed, must Shine led HL2. With a certain skill intensity of its light can be judged about the levels of voltage and resistance.
The device is applicable resistors of any type and any LEDs from the AL307. Battery GB1 - two miniature element (for example, SC) or two batteries.
If big break in use of the probe battery in it discharged, then recharged from the vehicle battery. To do this, the polarity of the probe device, connect the probe to the battery of the car. The time required to charge the battery tester - 5...20 minutes the Battery is considered charged, if you closed the probes of the probe is shining bright led HL2.
The design of the probe may be different. For example, if it the battery can be of two miniature disk batteries D-0,1, the device is easy to collect in the form of a bracelet, fastened with a strap on wrist.
Author: P. Bialiatski, Berdsk