Electrolytic capacitors from 1 uF to 220 uF can be tested easily with this simple device. With few components it indicates whether or not a capacitor is holding its charge through the blink of an LED.
Simply connect the capacitor under test to the circuit and wait a few seconds for it to charge.
Then pressing S1, if the capacitor has retained its charge because it is in good condition, the LED should flash.
If this does not occur it is a sign that the capacitor is not holding the charge and therefore in poor condition.
For capacitors above 47 uF the standby time may be more than 30 seconds.
The complete circuit of the capacitor tester is shown in figure 1.
As it is a very simple design, the assembly can be made based on a terminal strip, as shown in figure 2.
To test, connect a capacitor to the claws, wait a few seconds, and press S1. The LED should flash.
For a faster test you can reduce R2 to 22k or 33k.
List of materials
LED - common LED of any color
B1 - 9 V - battery
R1 - 100 ohms x 1/8 W - resistor - brown, black, brown
R2 - 100 k ohms x 1/8 W - resistor - brown, black, yellow
S1 - Pressure switch
Several:
Terminal strip, battery connector, claws or probes, wires, solder, etc.
