A gas stove igniter circuit

This article introduces a gas stove igniter circuit and maintenance information produced by Nantong Transistor Factory. Its circuit schematic (see attached picture) was drawn based on physical measurements during maintenance. The circuit structure of this igniter is very simple. VT1, R1, and T1 form an oscillator. VD1 charges capacitor C2, and the voltage at the end of capacitor C2 rises, until the C1, VT3, and VT2 branches break down. After VT2 is turned on, it discharges capacitor C2 to form a high-voltage discharge circuit of T2, and the cycle repeats. The power supply is a No. 3 battery, and the button switch S1 is used to control the power supply. As long as S1 is pressed to turn on the power supply, an intermittent discharge arc of tens of thousands of volts will be generated in the discharge gap.

A common fault of this type of igniter is that after pressing the button switch S1, there is no discharge arc at the ignition head (discharge gap). There are usually three reasons. One is that the battery energy is insufficient. The second is that the ignition head is dirty. The third is to prevent it from being sprinkled with water, let alone falling into a pool or basin. The fourth is that the electronic components fail, the most common of which is VT3, VT2, and VT1 are damaged.

TAG92 (VT2) is a low-power bidirectional thyristor, and its electrical parameters are shown in the following table.

There are many alternative models of TAG92, such as TDA92, TAS92, SC92B, BCR1AM12, SC92D, TXC0310, TCS92, TCD92, MAC94A4, MAC95-4, BCR1AM4, NTE5655, etc.

3AX31B (VT1) is a low-frequency, low-power triode made of germanium. It cannot be replaced by a silicon tube unless the circuit is modified. Even if a germanium tube is used, its amplification factor cannot be too low and the penetration current cannot be too large.