68 A clamping diode

In several of the oscilloscope tests on actuators, mention is made of the voltage 'spike' that occurs when the device is switched off. In cases such as relays, horns, electric fan motors etc., the circuit that operates the device is equipped with a diode that 'blocks' current. This is known as a clamping diode. Figure 6.22 shows the type of waveform that can be expected from a test on these devices.

Secondary current: iqnition circuit 2-3

Fig. 6.20 The HT coil connections

Secondary current: iqnition circuit 2-3

Fig. 6.20 The HT coil connections

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